Ah yeah, you're right, all of those legally sounding words invalidate actual use.

Yes, I buy things with bitcoin, and no, you can't find it on the blockchain.

(Or do I? :))

I’m not doubting that you use it, only pointing out that it’s not free to do so.

Similarly, maybe you haven’t hit a transaction yet which a government made an effort to block but … are you certain that nobody will ever try to do so or be interested in your past history? If you’re trying to obscure your identity, consider how that would look under existing money laundering if any party led to your real identity being associated with those transactions. If you aren’t confident that no government with jurisdiction will ever care, that’s a factor to weigh on every transaction since you’re leaving an immutable public record.

> Similarly, maybe you haven’t hit a transaction yet which a government made an effort to block but …

They wouldn't be able to unless they had over 51% of the mining power, and it would be easily noticed.

That’s assuming that a direct attack on a network is the only option. What I described was much easier: if the government requires payment of taxes or reporting real identities, you’re going to have trouble exchanging into real currency unless you’re paying enough for someone to risk money laundering charges. Similarly, if a commercial exchange is required to refuse transactions traced to an address on a list, it’ll effectively limit their ability to use the network. Most companies aren’t going to risk their business on those transactions even if they’re technically capable of processing them.

Since the blockchain is public all of that can be retroactive, too, so any transaction has the risk that the other party will leak your identity, which similarly disincentivizes other people from taking them.

None of that is about actually blocking the transaction, it's just about possible consequences of making the transaction.

By that logic anyone in the world can "block" whatever they want by threatening consequences.