BTW, it super pisses me off that people can't answer this type of question clearly and directly.  The thing you've asked for, a simple QR code to allow for easy bitcoin payments, is probably the #1 question of anyone that has learned about self-custody and is now ready to do some business with bitcoin.  "How the fuck do I incorporate bitcoin into my business?!"   Well I think custodial LN addresses are the simplest way.   Self-custodial LN fucking sucks and is impractical for 99.9% of people.  

Eventually when the account starts to fill up you can send to on-chain address.  You can do this directly from Mutiny Wallet.   EASY.  FUCKING.  PEASY!!