Would blockchain work better for the Fediverse, instead of Email Style Instances?

I recently came across three separate platforms:

Qortal: https://qortal.org/

ZeroNet: https://zeronet.io/

and

Plebbit: https://plebbit.com/

That all claim to be completely decentralized.

There's even talk about how Plebbit is more decentralized than the Fediverse, because the Fediverse is based off of instances.

https://www.reddit.com/r/javascript/s/0ynXzrD5H6

And I was curious, would such a setup work better for the Fediverse, or is it basically just a huge scam/waste of time and money?