But there is a great joy in being able to release a new utility and say about it, "This is how it should work." It reflects your own desires, you understand it, you made the decisions that went into it and have actually thought about the alternatives. There's a delight there. It could be a sign of a piddling egotist, or of a developer who is excited about what real users get to see.
(I did this sort of thing once -- reimplementation of commonly-used, if more niche, thing + manifesto -- from more than 20 years ago: http://all-day-breakfast.com/wm2/)
My main hope for anyone doing this kind of thing is that not too many people actually use it. You don't want to get stuck supporting a tool like this for the world and its dog.