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 !
I'm sure bitcoin online wallet are is not small company,they have good marketing plan and have great profit management,i think they earn profit from transaction fee,not witdraw fee,its why they have bitcoin exchange and market,and also they join with some others company to advertise and promotion.
I think thats coin doesn't no fee for every transaction because they have a market place or trading place.. also maybe they own miners instead confirming from other miner their own miner will confirm and accept miners fee.. this is just my thoughts.. maybe there's other reason.. for xapo maybe they are get many visitors from their many faucet thats why the fee for every transaction is free..