I came across this advice on niche OSS projects. It is sound, not too long and I fully second the wrap-up:

So getting back to your project, I think that may be what you need to explain to your boss: that substantial work is needed to make software usable, and that’s a prerequisite for use, which in turn is a prerequisite for contributions. If that’s your goal, then you need to work more. If not, then please make it OSS so that when I stumble upon your project in 3 years and want to use it, I don’t need to reimplement it from scratch first.

This short paragraph defines the aims of most small programs: either it’s useful and will live on it’s own, or it will die but eventually help someone in the future who picks up the pieces.