How does mints inside a frame work? Is it actually minting on a chain?

yes. The address you link here is the reference / deposit address the mint gets deposited to. It works by using minting contracts with gasless transactions

crypto software engineer

planet earth is blue and there is nothing i can do

It is probably possible to charge for mints here too: a smart contract that you have to connect and approve spending for a specific SPL / ERC token; and then afterwards once you click mint on this launchpad contract (which you have approved beforehand) it spends from your wallet and deliver for u

solidity dev. founding @bbbdeals. i interview crypto devs on web3galaxybrain.com

Oops, seems like Payable frames on the way too, wouldnt need allowance:

Oops, seems like Payable frames on the way too, wouldnt need allowance: https://warpcast.com/dwr.eth/0xff55c0aa