For me, the creation of a new universe starts with the map. For others, it's the languages. I've always wanted to be the kind of person who could delve deep into the languages and philology of the worlds I created, but I would never get any further than creating a few simple words. This tool is great for someone like me: it'll do all the work for you. I've also seen praise from conlang-era who find it helpful if they need to quickly flesh out a language they've been working on.
If you're into worldbuiliding in any way, Vulgarlang is definitely worth checking out.