Where as an average 2 burner propane stove take about 3.5 minutes to boil about 1L.
We are on a completely different page here. When camping in the middle of some desert during winter, or at a considerable elevation, cold wind blowing, maybe almost freezing temperatures, it may take 30-45 minutes to boil water with a small stove. Even a regular full-sized one can have a hard time heating up the cold pot while wind is blowing. 15-20 minutes is not uncommon.
On the other hand, if the weather is nice and no wind, there is no need to rush and have hot water ready right away.
I see the electric boiling more like a way to ensure the morning starts OK even in the worst case situation.
Anyway, I got a use case where the inverter is a good idea indeed: inverter very close to the battery and then a 110V line that runs inside the tent so an hot beverage can be prepared there without even getting out of the sleeping bag. Just remember to put the water in the 110V water boiler the night before, in case it freezes overnight.
just at a slower rate, so it will take longer to heat the water. Probably at that point, longer than the stove. So I'm still a stove fan. LOL
We must do very different kind of camping!