By the time you think they might have been of some use to you it will be too late.
You should join because there is no other pilot representative body with anything like the same influence. If your local council has not represented you well enough, then you should stand for election, get on the local council and then you'll have the influence and authority to change things for the better.
You'll achieve precisely nowt by standing on the sidelines griping about how useless you think they are and how they're not worth the money - there's plenty of people like that and guess what they achieve.