I've "participated" in a number game jams as a means of exercising my gamedev skills. What I do is I look at a particular game jam theme and ruleset and then adhere the development within that box. The only thing I don't do is submit my result for people to evaluate. The reason for this is because I don't have the time to develop a game jam within the submission deadline, the game jams that I develop happen long after the deadline.
I recommend doing game jam restrictions as a means of exercising creativity in the game dev niche. One particular technique that's very interesting is the concept of "one button" games.
https://dev.to/abagames/how-to-realize-various-actions-in-a-one-button-game-fak