IIRC these sort of "Oventtes" were popular to take along camping and or at "the cabin", wherever the latter happened to be.
It's worth remembering how bad housing shortage and situation was not just before, but for long time post WWII. Cold water flats were easily found before the war just as afterwards, and people considered themselves grateful.
Then of course there were rooming houses, SRO hotels, and other places which were pretty much just renting a room.
In many instances a hot plate, "Ovenette" and or similar contraptions were what was on offer for such living.
There were also various sizes of electric roasters made by Nesco, Westinghouse and others. These could function as primary or secondary ovens as well.