yeah, I have one PowerVent gas water heater, and it has notched settings that allow temps up to 180...
all bathroom faucets are scald-safe units....those are set to give a luke warm shower....now in the master bath, I bypass those set temps...
even my regular vent gas water heater allows temps up to 160.....
I would say that for a single person lower temps would suffice, but not really the case for me, as when it was just us two, gas is cheap enough to allow me to run temps that high....
and there are times when running several machines, a dishwasher, and having up to 10 kids, the on-demand is ready.....at a lowest temp, to mix a warm bath, you would need 60% hot to 40% cold...but at the highest setting, you may only need 30% hot water to a 70% cold.....I have never run into a case of running out of hot water when there is a high demand...
washing in hot or true warm temps, has proven to keep my machines running at top condition.....we all have seen the effects of washing in cooler to cold temps does to a machine...
I was never wild about having an electric water heater, but when we did, it seemed best to add a timer to it....but you did have to work around when the hot water I could see where heaters in machines set availability.....I could see an internal heater may be of help...