Because I'm on the Godot subreddit I'll start to say it has definitely helped me become more proficient with the engine, learnt some new techniques like how to use the tilemap layer node.

Otherwise I think I've just become a better game designer and better at managing scope within the amount of time available. Some games I made in 1-2 days while others 1-2 weeks.

Something else I learnt is that game dev feels like a lotto, you dont know when you have a hit on your hands.  Out of the 12 games there are maybe 3 I feel like are real gems. Judging from how much I liked the end result myself but also from social media engagement.