On this side of the pond they are used all the time! :) As are milliliteres...
Here cups are very rarely used. Certainly not for dry things like flour or sugar, and not for butter! Those are all done by weight.
Recipes are often given in imperial and metric measures here: one uses one or the other, as they are not exact translations. My kitchen scales with measure liquid and dry quantities in imperial or metric, oz/fl oz or kg/lt. I usually find that kids will choose metric, but use imperial quite happily if it's an old recipe. Same with sewing: all my quilting kit is in imperial, and that's what I usually use to sew. It doesn't faze the kids if you explain, and they feel quite clever to have mastered some new mathematical skill while actually doing something else! :)