The Pixel buds also charge on the stand right?

Yes.

Or is it just so you can charge both phone and the buds at the same time?

Exactly!

I have banned my cell from my bedroom, so each night I place my phone and my earbuds in one spot on the desk. Also, I leave my phone docked on the Pixel Stand during the day and work hours, which lets it double as a bit of a digital display and control for music/podcasts.