exactly what they were designed for.
though, the fraction "push me up by my alts" has grown too big.
i noticed that.
but i think that the gem exchange is too important for the game, to be deleted for just a few guys that got so strong alts (well, they can't be really a lot, can't they?).
and i also thing that who has an hokage alt, almost deserves gems exchanges...i'm not talking about me, since my alt is a lvl 1 genin
still, how about having it only for hogakes? maybe sannins and up could have access to hoshi, but only hogake could get to coffers...
that wouldn't really solve the problem completely, but not many people could use that. maybe so little people that you could allow it...
dunno, just a suggestion. you're the boss