We will transfer NFT from our vault wallet after recieving a request for buying specific NFT by user.
This means that we transfer the requested NFTs to the user as soon as we confirm that the user has made a payment in legal tender. Therefore, our sales (or, in other words, the sales of the business that wants to sell NFTs) come in legal tender, and the crypto assets are simply consumed each time as gas money.
The only legal regulation to consider would be the accounting and tax treatment of the crypto assets held for the gas bill.