What they say about moisture damaging IEMs is true, however if you just make sure to keep them dry (maybe with a towel or something) it should be fine. Granted that chamber probably dries them better (miniscule droplets could still be left with conventianal drying most likely), not to mention is a nice hard protective case. Depending on which IEMs you use it may be worth it (I'd say customs, at least the Westone ones, come with their own, and maybe something like the CX300 or E2c doesn't really need one all that badly).
EDIT: The E4c is probably worth the investment. The moisture remover is pretty durable as well, and since you can 'recharge' it with a microwave, it should last a long, long time (well into your upgradeitis).