You sound like someone who gets all their news about crypto from the WSJ and NYT. There are many use cases beyond paying hackers. And believe it or not, hacking was profitable before crypto! As was drug dealing! But HN commenters act like Bitcoin created the industries.

As a law abiding person (in the UK if that matters), in what use case would bitcoin help me?

I don't have any particular hate for it, I would use it if it benefitted me, but I can't see any situation on the horizon where that would be the case.

If brexit tanks the value of the pound, then BTC can protect your wealth (along with equities, bonds, gold, etc.).