@Linky generates nostr account during onboarding. Actually using npub.cash for lightning address. Using cashu and you can send to lightning anytime. (Hopefully soon even onchain)
Proxy payment is specific feature. Linky stands on trusted connections - friends. We test it now in Czechia only.. There is quite common to pay on eshops via QR - bank transfer - immediate and with no fees to VISA/Mastercard. The proxy payment means that you ask your friends if they could do the bank transfer for you and you give them sats for that.
So your friends stack your sats (when merchants don’t want them) and you can use bitcoin even more and building your network on the way.