According to Wiki: "NFT"
A non-fungible token (NFT) is a non-interchangeable unit of data stored on a blockchain, a form of digital ledger, that can be sold and traded.[1] Types of NFT data units may be associated with digital files such as photos, videos, and audio. Because each token is uniquely identifiable, NFTs differ from blockchain cryptocurrencies, such as Bitcoin.
They are categorized based on their being tokens not Bitcoin nor physical.
Note that in all Bitcoin boards we are talking about Bitcoin as a payment method or Bitcoin related topics, both of which are not found in NFT tokens.
you can sell NFT digital things ( scripts, exchanges, ..etc) in Digital Goods if they can pay with BTC