They work in the US too.
I live in the suburbs, I ride my bike up to my house, then into the yard, then in the back door, then stop in the bedroom and plug it in. I have a higher end model(1500w motor) and I commute 5 miles each way to San Francisco daily. the bike is faster than driving, and I've never ran out of juice, and I can tell down to the mile when I'll run out due to the very accurate power meter. I"m sure the bike would be stolen in 5 minutes were I ever to leave it outside, but it spends the day in my office and night in my bedroom.
I believe the trick with E-bikes is that everyone may or may not be able to use one, depending on their individual circumstances. You need:
1. A place to park it safely indoors at night
2. a place to park at your destination
3. no stairs
4. less than 10 miles each way of commute
5. willingness to deal with weather and assholes and danger.
That all said, I'll be donning helmet, rain gear, and gloves tomorrow morning.