The NEP-171 is about the equivalent of the ERC721. It's just a guideline to enabling other platforms to interoperate with assets, giving them confidence the nft_transfer and ownerhip verification.
Anytime you see the
nft_ in front of a function, this is help indexer identify what's going on. In Ethereum land, every contract indexes on its own chaos.
We took it a step further and added a payouts system which gives marketplaces less excuses by giving the, easy access to royalty expectations.