Some inspiration from Derek Yu (maker of Spelunky) on why it's so important to finish a game:
> Holy crap, you released a game! Congratulations, you just leveled up, big time. Benefits include: increased confidence, a reputation for being able to complete projects, and an understanding of the entire process of game creation! The best part, though, is that you have a nice little game that I can play and enjoy! And I do like playing games, almost as much as I enjoy making them.
https://makegames.tumblr.com/post/1136623767/finishing-a-game