As BigBoss states, larger screen sizes will benefit from 4K far more than smaller ones. The average domestic TV nowadays (50"/60") doesn't really warrant it, as you'll not really be seeing a decent jump in performance until you're using something like 5ft screens and larger, as used with home theatre projectors. Viewing distance plays a big role in this, and most people don't sit close enough to a 50" TV to get any real benefit - except for 3 year olds who sit 2ft from the TV, but I don't think they're really that bothered about 4K when watching Peppa Pig.
As for curved, I think that will be a fad. Again, no benefit to the viewer, as it is a feature that was originally designed for users of very large projection screens in order to keep the outer edges in focus.