Good point to remember. But isn‘t that the case for any (non-custodial) wallet? Fees are everywhere and with nostr:npub1xnf02f60r9v0e5kty33a404dm79zr7z2eepyrk5gsq3m7pwvsz2sazlpr5 you at least have a clear information about them. Plus, they clearly state in their documentation that the initial transfer should be > 100k sats. Custodial wallets probably don‘t levy such fees because they can sell your info/data and, anyway, they have your sats 😉