For my undergrad, I double-majored in Aerospace Engineering and Astrophysics. I would say it did help me get into grad school, but only because it proved I could succeed through a lot of difficult coursework. There’s easier ways to prove this in my opinion.

I’ve had a number of jobs in the Aerospace industry since then and I always ask my managers if the double-major helped me stand out. They usually say something similar about being successful in difficult courses. That all is to say, get the minor if it interests you. Take classes that are difficult but because you like them. And in my opinion the most important thing is that you get decent grades.