There are many online wallets like Xapo and Coinbase that do not charge any transaction fees or they pay that fees by themselves. I want to know that how would they profit from paying for their user's transaction fees ?
If no fees is charged then the transaction take a much long time or even might get cancelled !
they have profits from ads, if a lot of peoples are using it means that a lot of peoples see that ads and they earn good profit from that
From ads? I never seeing the advertise in the blockchain and maybe the source income for surviving just coming from the tax fee from every transaction. but for blockchain, i'm not feeling doubt about that because every second is always there a transaction.
Coinbase and Xapo wallets do not have ads in their sites so that is not it.
These sites are both wallets and exchangers themselves so from that information, they survive and successful in their business most probably from the earnings they get from selling/buying bitcoins.