No one would ever look down on doing something you're interested in, it might spark a conversation sometime. That being said, there are probably "better" things you can do over the summer (in addition to the course) if you want to impress adcoms.
Also a piece of advice about taking "easy" classes, while the course material may be easy to grasp make sure you actually put in the time to get an A. When I took easy courses I quickly found them to be more of an annoyance, there's nothing worse than being forced to do a boring homework assignment in a class where you just want to learn for fun.. except maybe then getting a B+ in your easy A
