VP Biden Needs an Economics Advisor?

I have long been puzzled by the fact that throughout the US's history, the Vice President hasn't been utilized more. In particular most of Biden's days seem to have been spent with "no public events scheduled."

So reading through Wikipedia's entry on the PERAB today, I was surprised to find that:

He mentioned James K. Galbraith, Larry Mishel of the Economic Policy Institute, Dean Baker, and Jared Bernstein as progressive economists who might be suitable for the board. Bernstein, however, was subsequently named to a full-time administration position as chief economist and economic policy adviser to Vice President Joe Biden.

And I'm wondering, if the President has the PERAB, and presumably his own economics advisor, why does Joe Biden need one? Can we assume he's being paid more than $100,000 a year?