Because they said so, that's why.

I've seen some old men screaming at clouds when it comes to crypto, but the interesting thing here is how little investigation or justification of their points they feel the need to make. Considering the IMF and pretty much every major national reserve has at least made inroads into "maybe we should prepare for this stuff" to have the BIS go

“Without users, it would simply be a worthless token. That’s true whether it’s a piece of paper with a face on it, or a digital token,” he said, comparing virtual coins to baseball cards or Tamagotchi.