If you own a domain - let's say domain.tld - and can run a rust app, you can host this project that allows people to get a @domain.tld lightning address

hey! it lets you use the domains you own for the purpose of lightning address (https://lightningaddress.com). So, assuming you've got cool-domain.com and would like to use it in order to receive lightning payments at my-name@cool-domain.com you could start the mentioned project and use it to set up that lightning address properly.

If you like the satspay.to domain and would like to claim btc_ln@satspay.to (for example) you can simply go to https://satspay.to/ in order to make that alias yours :) After that, all the payments that get sent to btc_ln@satspay.to will land directly in your LND/LNbits wallet. In many cases it's just easier to memorize email-like address vs passing ln invoices/qr-codes around