I think this is why they're supposed to be limited to 800 W, but is that enough to avoid serious danger to utility workers when a whole apartment building or neighborhood is full of these?

Central Europe has more buried electrical systems and nothing is safe until it's actively grounded so hard it'll arc flash the idiot who broke you LOTO before you even feel a clear tingle.

The 800W is about grid management impact limitation to levels that do not warrant the utility imposing any "but we first have to upgrade the substation before we can get you your local transformer with the higher speed EV charging and McMansion winter full heat pump setup" delays before you are allowed to turn it on/grid-tie it.

They are limited to prevent fires. They sit behind the breakers so any power they feed in allows more current on the cables before the breakers trip.