My (manual) car has hill start assist. It was a bit weird to get used to but it isn't a problem now.
Maybe it's the automatics that I've driven, my mother's Honda Jazz and my dad's Audi multitronic, both CVTs. It seems to be something to do with the automatic clutch. In s manual car, it's quite easy to let the clutch out until it just bites, then foot off the brakes and you can control your speed reversing out of the driveway just by modulating your left foot on the clutch.
The automatics seem to want to disengage to prevent a stall or something, so I end up having to use both feet, giving petrol to actually engage the clutch, and controlling speed with my left foot on the brakes which is hard because since I'm not a racing driver I'm used to braking with the right foot.
Maybe other skilled drivers don't struggle with this kind of problem with automatics but I do.