Edit: That argument is just "trickle down economics" with extra steps.
I disagree.
Billionaires have outsize influence. They buy politicians to set public policies that affect the working class and divert billions of our dollars into their pockets.
If you put all of their money in a pit and set it on fire, it would have a greater impact than just taxing them 2% and spending all of it on public programs, because they would no longer be able to do harm on a billionaire scale.
The people could heal.
We'd still have other beasts to deal with, but the existence of billionaires is a cap on the lives of the working class.