I suppose in very cold places, there are issues I haven't thought of. Honestly though, I think it's more about how novel and shiny it feels. It makes (made?) the car feel a little futuristic in most cases. A sort of signal a potential buyer that this is the next generation of car..

I think the trade off makes it not worthwhile. If it's optional, I prefer a normal key.

OTOH, There are lots of other cool gadgets that I'd like to see. A car that remembers everyone's seat position and mirrors, that's progress. Manual transmission, normal key, smart seat. That's my niche.