Who said that? It can be banned, but the ban is costly to enforce and thus just drives it into the black market. And so any bitcoin user would much prefer to live in a jurisdiction that is not authoritarian enough to ban the use of a decentralized spreadsheet.
Discussion
Your Bitcoin friends say that. Representative example:
Well governments can ban it, and lots already have. But they can’t literally stop people holding or using it. The question is whether there is a difference. If there’s jail time for someone saying they’re using it then things have to get pretty dystopian before people will take that risk