Physics is math that touches the ground. Not only do you avoid the temptation to muck around with "inaccessible cardinals" and things like that, but I get the impression good physicists can just work out a lot of things from first principles.
Physicists have an excellent nose for modeling too.
edit: I don't think knowing more physics would "help me" now, in the sense that I don't need to know more physics to write papers. But I think knowing more physics would help my intellectual development a lot. I am working on it...
I am not sure my experience generalizes, I certainly am not advocating studying physics as a universal piece of advice.
As a physicist, I'd like to say that if you're tempted by inaccessible cardinals, you will still end up mucking about with them, much to the annoyance of some of your cohort.
I was looking at a discussion of what should be in a college curriculum, and as such discussions seem to go, there was a big list of things everyone should study, and some political claims about what's being offered but shouldn't be.
Instead, what do you wish you'd studied in college? What do you wish other people had studied in college? On the latter, do you think everyone should have studied it, or do you just wish more people knew about it? Approximately what percentage of people?
Of course, this doesn't have to be limited to college. People could learn the same things earlier or later.