Mityvac 8510?

I had a cheap something or another brand hand vacuum pump. Might have been an old Harbor Freight. It died by compression! 😂 I drove over it.

I decided to get a nice one. I bought a Mityvac 8510. I was intending to get the 8500 but for some reason when I saw the 8510 I thought that was the one that was recommended to me.

Anyway the 8500 only does suction (vacuum) the 8510 also does pressure (pushing air in). So what’s the use of a pump like this that will force air in on a car?

Thanks!