Regarding your use cases.

> uncensorable payments

would your corrupt country not eventually catch up by regulating the ability to convert your BTC into fiat to buy things, or do you anticipate doing all your payments on the blockchain and never converting to fiat?

> also super quick payments (donated to Ukrania during war ar Sunday night < 30 secs)

a global payment system does seem very useful, assuming the currency is stable; not justified to the current hype though

> moving the ownership of items to a decentralized system (e.g. NFTs as trading cards)

I have failed to understand this one. If you own NFT 1 on Blockchain X, how do you enforce your ownership rights in the real world if someone else chooses not to acknowledge the authority of this decentralized system? If it's a real world asset, and I steal it from you, who do you appeal to? If it's a digital asset, and I copy and use it, who do you appeal to? Or is the utility here people who all buy into and respect the authority of this chain's ownership ledger being able to trade these things within that ecosystem?

> smart contracts (lock your tokens and you're guaranteed, by code, that something happens like being paid an interest at some time/logic trigger)

I haven't found this one that compelling, but maybe I'm missing something. Code isn't immutable, so what's to stop my "smart contract" from changing? I may be unaware of some guarantees that the blockchain provides that the code itself is also immutable.

While it's true that you can't really censor the blockchain transfer, how much that allows someone to 'take' a payment depends a great deal on the legal circumstances where they live. I don't mean that the core transfer mechanism isn't cool - but there's a pretty big gap between a digital currency and acquiring physical goods where authorities can step in.

> super quick payments

Blockchain technology is, on average, pretty much the slowest possible way to make a payment. The slowness of other techniques are not because of any underlying technical reason - they're based on laws and policies. It's true that it can be faster than other methods in certain circumstances - but that has more to do with gaps in regulation than the technology.

I fully agree that distributed ownership is cool, but I wanted to note something about this:

> I can have my trading cards on a privately owned server too, for sure, then I'm bound to them not banning me, not crashing and losing my data, not going bankrupt, not changing the rules of the game etc

You are still bound by them not crashing, losing your data, going bankrupt or changing the rules. Many blockchains have gone down, lost history, shut down entirely, or changed the rules. There are ways that these problems are more easily addressed in a blockchain ecosystem, but it's not straightforwardly "better." If your usecase suffers from a bug, and a majority of the nodes benefit from that bug, you will likely never be able to get that bug fixed on the main chain.

I also think that copyright is the elephant in the room. Imagine two versions of...a world of warcraft sword. One is the texture & model that are included with the game - the other is, additionally, an NFT. The material reality of adding that sword to another game are identical in both cases: you can just put the sword in another game if you have the assets. That has never been a technical challenge. The challenge is legal and NFTs do not help with the legal problems.

If I sign a contract with you saying you can use the sword in another game the contract is the thing that matters. It does not matter if the contract is in an NFT or references an NFT. If anything, creating a system to manage & mint NFTs is an additional technical lift in creating multi-game assets.

I'm hard pressed think of how NFTs would be better than a centralized server that publishes daily signed database dumps of all owned assets. The cryptographic guarantees are the same and in either case the service continuing to sell assets depends on their willingness to assign copyright.