Maybe but they've been around in Europe for a long time and (as far as I know) have never been banned anywhere over here. They still aren't commonly seen in supermarkets anywhere in Europe I've been or lived (you sometimes see them in farmers markets and the like) so I think growing them commercially generally just isn't worth it.
They're just not used a lot, at least in the UK, so they'll appear in supermarkets occasionally (perhaps only once/season) as a limited batch. Otherwise you could get them at the market or a 'pick your own' farm which (IME at least) tend to have more berry varieties than anywhere else.
If they were more widely available they'd certainly be used more. There's no shortage of rhubarb in supermarkets when it's in season, and gooseberries can be used in a lot of the same dishes (crumbles, fools, stewed etc). However gooseberries can also be used for lots of berry dishes. There's definitely a market.
