Hope there will be many more applications like this in the future. You can share your ideas in https://wintermute.app/ideas. Imho many services are missing, like a privacy first social network.
I love open source and maintain several open source projects. By making TimeTagger open source, I was hoping to find a niche of "tech" users. And if it fails, at least the code can be useful to someone else.
I hope I'm in a salaried, non time tracking role for the foreseeable future, but if not I'll look into TimeTagger.
>Do you see model like Ghost could be a strategy to grow Open Source SaaS products?
Definitely, I think Ghost is a very good and successful example of Open Source SaaS.