I have alt characters not for the storage space, but for the ability to sell more items. Once you start to have multiple professions, 40 spaces just doesn't cut it.

Allowing people to mail to characters on their own accounts would make things so much easier. I understand the RMT thing, but they're just sending the gil between accounts anyways, so this restriction probably doesn't harm them all that much to begin with. It certainly harms legitimate players far more, for sure.