It’s fine if it’s a passion. Schools like to know what interests you and then how you pursue that interest. There is a difference between having some money and investing it and actually learning about investment strategies, valuations, etc.
If I tell you I sometimes cook dinner, that’s a bit different from being passionate about cooking, taking cooking classes, cooking every weekend and experimenting, having a volunteer role in the kitchen at school, camp, soup kitchen.
We all do a lot of things to pass the time. But there’s not enough time for lots of passions. So if you mention this, frame it accordingly.