
Battlefield… 4? did it to a limited extent - the code was required for online multiplayer, but not singleplayer.
By Battlefield 6, and enough people absolutely loathing their existence, EA took the hint and didnt repeat that model. Though BF6’s campaign is apparently online-only, so they apparently pivoted to a different insane design choice.


Blockchain just means every transaction is recorded forever (simplifying a little bit but not too much). You can have a blockchain currency without any mechanism to exchange / trade / transfer it.
There are also even regular cryptocurrencies that can only be traded within a ‘walled garden’ where the house always gets a cut. But I don’t think they’d allow P2P sales, ever, and going by GTA V, probably won’t allow P2P cash transfer at all either.