You're right that sanctions and restrictions could impact the price.
What I'm arguing is that this impact doesn't cause the price to be zero, requires global coordination to have a big impact, and that even in this case, the self-custody capability of crypto is still something better than the alternative (no access to any funds or any ability to transact). We're also discussing an extreme worst case (and even in that case it's still better than frozen non-custodial fiat funds).
Flagging wallets to exchanges also requires targeting and many people wouldn't get hit by this. There are also a lot of cases that benefit from self-custody in a world that doesn't have this extreme global coordination to sanction crypto.
Imagine the case where you're a random Ukrainian citizen in Russian occupied territory trying to get your wealth out across a hostile border. Your crypto wallet is not likely to be flagged to exchanges (even if it was most exchanges wouldn't care). You can memorize the seed words and get out safely with the ability to recreate your wealth on the other side.
This has already happened at least once: https://www.forbes.com/sites/tatianakoffman/2020/06/13/why-b...