I think most of that volume is bot stress testing, so they can push the lightning network more and see what it is capable of. This also allows them to show that lightning can scale.
How much fees asked there for simple BTC to ethereum convertion ? Is this one working the same as shapeshift where you only need to transfer amount and you will recieve it in provided address .i use that website in early 2017 when they are not requiring kyc for easy trade but not now. Is that exchange also asking to be verified with identity required?