I suppose it depends on what you mean by compensation.

Delays are covered by EU261 and its UK equivalent, and I’m comfortable claiming that as, by-and-large, with the exceptional circumstances caveat for weather, ATC, etc, it means BA did something through omission or commission to cause me to be late by several hours.

Other financial elements of EU261 are really reimbursements, rather than compensation, for things like downgrades or duty of care. I see no issue with claiming for this (ditto things like seat selection fees that weren’t honoured) since that’s really about ‘making you whole’.

I’ve never (yet) had cause to complain for a customer service issue. I do try to live and let live, and not get too worked up about things like first meal choice and so on. But everyone draws the line differently, and I understand there’s some Avios to be made in it, if you’re so inclined.