That’s where you split difference. Get a functional bag with all the pockets and then accessories with the fun stuff. Put some wacky patches, pins, or stickers on there. Attach some keychains on the zipper pulls. Extra points if they’re the mini stuffed animal kind.* You could even decorate the handle and straps. A little or a lot it’s all up to you :) Bonus: it let’s you show off multiple interests.

*points in my book at least. Becuase I’m a sucker for plushies.