Both have increased the interest in Britain, basketball was already popular in continental Europe. Doing it year after year helps, and the games are always sold out.
NFL is still seen as an American novelty though - a bit like baseball it’ll never be super popular here because we have our own similar sports that are more established (rugby and cricket).
The biggest difference from the increased coverage and interest is higher participation leading to potential professionals, especially for basketball. When I was a kid I got the chance to play American Football only once, basketball hardly ever, and baseball never.