it seems like a good service. do you know what kind of fee they are charging (or maybe adding on top of their prices silently)? i've checked a couple of their prices and it seems like it is higher by about 1.8% to 1.9% compared to prices on Binance for the same coins.
that sounds about right. i've seen it fluctuate between 1-2% over binance.
i guess that's the price we pay for the privilege of not needing accounts, and not worrying about elliptic, cyphertrace, et al.
you also don't need to pay the typical exchange withdrawal fee (eg 0.0005 BTC at binance) which claws back a bit of the profits taken by instant exchangers like flyp.me.