People would have been hesitant to undergo and submit their papers to undergo verification because this will expose their personal infos however in the long run this can benefit the client. This can serve as their protection if ever their accounts would be suspected. However gambling sites /industry should ensure the confidentiality of client's accounts. And that it should not be used to go against their rights
I guess it cant benefit as there would be no need for that. No company or exchange take risks for client losing his/her password or giving to somebody else. And transaction level are irreversible, so KYC is useless for a client. But it gives more info about you to exhange and other people unfortunately. I use coinmonkey.io exchanger and they dont t require even email for transaction - only wallets.