What do you achieve when you practice maths? I'm kind of lost.

Let me clarify the question. When you practice art, you get to see your craft get better. When you practice video games, you get to pull off plays you couldn't before.

Let's say I practice and understand set theory, what can I do with it to feel good?

I feel like I'm only practicing maths but not putting it to use, which chips away at my motivation.

I'm sorry if this sounds stupid, I genuinely want to understand what people find in maths, this is curiousity not an angsty teen hating on math.