I suppose it's for the poor little dons who can't leave the hallowed Oxbridge atmousphere and try to evoke it in London...
I'd imagine that the majority of the members are old people, not the kind of thing that young undergrads would go for. If you want to be alone in teh company of strange old crusted men guffawing and talking about the good old days, how they almost got a full blue in cricket but decided that they'd rather play croquet and having to get up frequently to change their colostomy bags, go ahead.
If you want an elite atmousphere, try the Pitt club.
If you want fun (ish...) try the union.
If you want genuine friends and people who care about you and who are witty, funny and interesting, try your college bar.