On Trezor, you don't need to collect the shares into a one place. You start the recovery process, enter a share and you can move with the Trezor into a location of the 2nd share etc.

Very nice, but Trezor is missing.

If I understand correctly, every bitcoin purchase on Relai is on-chain transaction. Aren't you afraid that you lead customers into creating many small UTXOs which might be very impractical in the future high fees environment? Thank you.

Mac runs premium sector of personal computing. Windows runs majority of personal computing. Linux runs the rest of the world.