That's not the UK's independent AI advisory board, it's an advisory board to one specific govt body which is part of a specific govt deparment. Not 100% clear why having an independent advisory board is something to aspire to.
I think the idea is that it's not influenced by politicians who don't know anything about the topic.
That definitely has value if the politicians subsequently listen to the advice. In the UK at the moment that is sadly unlikely.
In that case it's useless and disbanding it is sensible, no?