I always have multiple projects to work on. Sometimes it's hard to find inspiration and motivation while working on a singular one. Having multiple projects, allows me to take breaks. Working on game project can especially be tiresome as a single developer and having to take care of everything.
Maybe it's hard to actually finish a project, but for me working on games is like solving puzzles. I like to make games just to challenge my mind and see what I can achieve with just a bit off thinking and imagination. A cool game at the end is just the icing on the top. That's just how I see it as a hobbyist.