1 There is no escrow protection, if the seller bails or simply doesn't send the order you are done.
2 There are no reviews on messengers, so no consequences when a seller fucks up/over.
3 You don't get to build up your own reputation on the transaction since the order is not part of little biggy.
4 The little biggy community is undermined when people use it for advertising their own unsecured businesses. I appreciate having a place like this and if I can support it I do.
5 This type of behavior has a much higher correlation with fraudsters and security problems for buyer and sellers.