It is too complicated to manage one's own noncustodial facility for users arriving on Nostr.
Getalby however has now made things very complicated with the invitation code requirement.
The easiest zap management is to use Primal, with all the KYC and custodial wallet issues we know.
Neither is it easy to manage zaps with npub.cash or Minibits.
Of course, I am always talking about inexperienced users signing up for Nostr.
It's all extremely problematic and until I had nostr:npub14w5fpxvrhux6c9ecp82p5w3hxm46rh9tzktlr0e72sg8k9q57xwshqhg7u sign up I wasn't even thinking about it.