On the contrary to everyone here, I find that having better setups have increased my enjoyment of movies and games. In competitive games like Overwatch, it feels like cheating because the footsteps to me are extremely obvious. Watching movies on my two-channel setup, or even streaming on my computer to my headphone rig, is a treat.
That being said, you do not need a tremendously expensive rig to get such enjoyment, even if you were the type of person who listened to tons of music. There's some gear out there that have tremendous performance-per-dollar; for example, I'd rather listen to Magni 3+ over THX 789, Jotunheim (early version), Darkvoice, etc*.
*caveat: in a hobby like audiophilia, you really got to understand that much of it boils down to user preference. It really doesn't matter if someone else tells you if something is the best because you're going to be the one using it in the end, not them.
So yes, I think that upgrading is still "worth." You're going to find that movies have more coherency in speech, and the various sound effects will be "positioned" better. Same with games.