A bit of historical background 
Also, a lot of major appliances are not made as a universal design for the whole world as they may not be marketed worldwide.
Washing machines in general are quite market-specific and, in general, European machines are still made in Europe for European customers to European specs. It's quite unlike the consumer electronics industry where one appliance is made for the whole planet.
The 230V 50Hz market is also absolutely vast compared to the 120/240V 60Hz market. It's basically most of the planet, except the US, Canada, Japan and a few other places.
220-230V 50Hz European-derived standard, but it applies in the EU/EEA countries (507 million people, world's largest single market), all of the former Soviet Union / CIS (276 million people) , China (1.33 billion people), India (1.17 billion), the entire African continent (1.1 billion people), Australia, NZ, as well as a large chunk of South America. Half of Japan also uses 100V 50Hz..
So, all in all, you can be a consumer appliance manufacturer and not even think about 60Hz. There's an utterly vast market for 50Hz products, usually to a European-like spec. in design too.
The divide was fairly simple really.
In the US, Westinghouse was the main driver behind AC power in the early days and they decided on 60 cycles per second. It was fast enough not to flicker noticeably on incandescent lights and generators didn't have to spin ridiculously fast. 60Hz makes some sense as it's 60 cycles per second and there are 60 seconds in a minute and 60 minutes in an hour. In the early days, synchronising mains frequency with clocks and using it as a driver for accurate clocks was a big selling point so it made some logical sense to them to pick that frequency. (3600 cycles per minute)
Meanwhile in Europe, the main drivers behind the 50Hz standard, which was developed in parallel to the US system, were the likes of Siemens, AEG, ASEA, Ferranti and English Electric, Alstom etc etc...
From a European perspective, 50Hz made sense as it's 100 peaks and 100 troughs per second (50 complete cycles per second). The European preference tends to be for metric, so to the electrical engineers here it made a absolute sense to pick a number that fitted into something mathematically related to 100.
It's also 3000 cycles / minute which is a round number.
Again, 50Hz was fast enough to produce no noticeable flicker in incandescent bulbs but, slow enough to not provide any great engineering difficulties for the generation stations.
There's really no technical advantage or reason to prefer one to the other, they're just electrical conventions. The most important thing is that you pick and stick to one or the other, or it makes life VERY complicated!
220V seems to have been arrived at in Europe quite early on. I know Irish electrical systems were standardised at 220V 50Hz certainly by about 1925, and the standard definitely predates that by a couple of decades.
The first commercial AC power plant was opened in Depford in London by Ferranti in the 1880s. It predates Westinghouse's use of it by quite a while. That station was connected to a 10,000V local grid and output power at 83.3 Hz (5,000 cycles per minute.)

Also, a lot of major appliances are not made as a universal design for the whole world as they may not be marketed worldwide.
Washing machines in general are quite market-specific and, in general, European machines are still made in Europe for European customers to European specs. It's quite unlike the consumer electronics industry where one appliance is made for the whole planet.
The 230V 50Hz market is also absolutely vast compared to the 120/240V 60Hz market. It's basically most of the planet, except the US, Canada, Japan and a few other places.
220-230V 50Hz European-derived standard, but it applies in the EU/EEA countries (507 million people, world's largest single market), all of the former Soviet Union / CIS (276 million people) , China (1.33 billion people), India (1.17 billion), the entire African continent (1.1 billion people), Australia, NZ, as well as a large chunk of South America. Half of Japan also uses 100V 50Hz..
So, all in all, you can be a consumer appliance manufacturer and not even think about 60Hz. There's an utterly vast market for 50Hz products, usually to a European-like spec. in design too.
The divide was fairly simple really.
In the US, Westinghouse was the main driver behind AC power in the early days and they decided on 60 cycles per second. It was fast enough not to flicker noticeably on incandescent lights and generators didn't have to spin ridiculously fast. 60Hz makes some sense as it's 60 cycles per second and there are 60 seconds in a minute and 60 minutes in an hour. In the early days, synchronising mains frequency with clocks and using it as a driver for accurate clocks was a big selling point so it made some logical sense to them to pick that frequency. (3600 cycles per minute)
Meanwhile in Europe, the main drivers behind the 50Hz standard, which was developed in parallel to the US system, were the likes of Siemens, AEG, ASEA, Ferranti and English Electric, Alstom etc etc...
From a European perspective, 50Hz made sense as it's 100 peaks and 100 troughs per second (50 complete cycles per second). The European preference tends to be for metric, so to the electrical engineers here it made a absolute sense to pick a number that fitted into something mathematically related to 100.
It's also 3000 cycles / minute which is a round number.
Again, 50Hz was fast enough to produce no noticeable flicker in incandescent bulbs but, slow enough to not provide any great engineering difficulties for the generation stations.
There's really no technical advantage or reason to prefer one to the other, they're just electrical conventions. The most important thing is that you pick and stick to one or the other, or it makes life VERY complicated!
220V seems to have been arrived at in Europe quite early on. I know Irish electrical systems were standardised at 220V 50Hz certainly by about 1925, and the standard definitely predates that by a couple of decades.
The first commercial AC power plant was opened in Depford in London by Ferranti in the 1880s. It predates Westinghouse's use of it by quite a while. That station was connected to a 10,000V local grid and output power at 83.3 Hz (5,000 cycles per minute.)