We are basically a Bitcoin ATM, just digital. You put money in and get bitcoin out, and vice-versa. Relai never holds your funds and is also regulated like a Bitcoin ATM, namely as a cash exchange business. Such a business can be pursued without having to register or verify customers as long as the governing Swiss AML laws are being followed.
For Relai this basically means ensuring that the sender of money and the receiver of bitcoin are the same person, and that no customer exchanges more than 1’000 CHF per day & 100’000 CHF per year.
We do ensure this with our setup, and therefore yes: this is legal!