The club membership is available in three different flavours ranging from €150 / year up to €500 / year.
Depending on the membership level you get a few perks, such as discounts on parking, discounts on lounge access and fast track security access.
The problem is that the club simply doesn’t seem to offer anything attractive to frequent travellers. If you fly frequently you’ll probably have status from one of the airlines, which will give you lounge access as well as access to the security fast track. It’s not as if the security lines in Dublin airport are that long anyway …
Priority Pass doesn’t cost that much per year and you can get it for free with some of the Irish banks ..