Phone running badly? Factory reset it to fix things.
Pardon my interrobang moment, but that's ridiculous. Not that it's bad advice because it can often fix things, but it's a thing we should never have to do. When the "fix" for your software is to delete all its associated data and start fresh, that means your software is bad. Full stop.
There have been times where people have had to do this on iOS as well, so don’t take this as an Android vs iOS thing. Having to do a factory reset is a terrible fail state.
I’d say the same thing about anything that asks a non-developer from opening a command prompt.