> NFT's are not legally binding contracts
> NFT's don't prevent fraud, or theft etc - so you still need experts to authenticate the art if you wish to do a transaction.

Right but certificates of authenticity do not prevent fraud, theft, or illegal copies either.

I have limited knowledge of the "art world", so don't take my word for it, I'm just reporting discussions that I had with friends more knowledgeable on the subject.

My understanding is that nobody really cares if you have a copy of a photograph or digital art. What people care about is if you pretend to own it.

> you still need that artist to prove that they created said NFT for said artwork.

Well no, the NFT contains the signature of the artist that created it. That is, at a basic level, what an NFT is: a small token (often in the form of a json string) that is signed by a creator. This token can then be transfered by the current owner to others, and such transfers are on the blockchain.

Anyone can check that an NFT was issued by a legitimate artist by checking the signature of the artist on it. Anyone can see who is the current owner by following transfers of said token.

> You think that's bad today, wait until you need to do this on a public blockchain that has no built-in mechanism to unwind mistakes!

There is nothing to unwind on a blockchain, because you cannot create incoherent ledgers. That is why blockchains are perfect settlement systems.

Imagine the following typical simple settlement scenario:

1) You send USD to your brokerage account, willing to immediately spend it on some stocks. You do that through your credit card, which has a 3 day redemption possibility o such transfers.

2) Your broker does not want to prevent you to use that money for 3 days, because that would piss you off. So he "advances" the money to you, expecting that you won't cancel your credit card transaction.

3) You buy a share of Microsoft and see it appear in your portfolio. You sell it 2h later for a small profit. You probably don't realize it, but equity settlement will take at least 24h, so you did not really bought that Microsoft share. Also, you cannot really resell it immediately because you don't have it yet. Your broker will still allow you to do that "on margin", which basically means that he will again "advance" the cash and shares for you.

4) Since you made some gains by reselling your Microsoft shares, you can now afford a share of Amazon.

5) etc.

This is a very simplistic example. In real life these problems are amplified tenfold, because you have to add credit lines, derivatives, swaps, FX, currency settlement, etc.

But the overall idea is here: everything that seems "simple and fast" in finance is just because there are layers upon layers of local caches, that are settled together at varying time horizons, and generate mismatches that need to be handled.

A blockchain ledger is settled by construction. That is, if I want to buy Token1, sell it, use the profit to buy Token2. Then these very transactions need to be in the ledger, in this precise order, for the whole chain to be possible.

Blockchains _are_ settlement machines.

> Question is - why use blockchain? Nothing here is technically difficult with existing technology.

I think your question is backward. Blockchains do solve all the problems mentioned in my post. They solve it well, they allow any degree of customization that is possible, they solve it elegantly, and have been battle tested. Why _not_ use them?