You can run elderly software that was written for it.

At one point there was a paid app on Android that ran a VAX emulator. (A port of simh I think.)

A 1GHz phone ran the emulator faster than any real VAX ever was.

I once offered to set up a copy of an old corporate accounting "app" on said emulator for our accounting dept. (They occasionally needed to refer to old reports still available on the old VAX system.). On the chief accountant's own phone.

He said no.