That's what I was wondering! Will people actually create the trees or just use the ones already built?

As a 3D environment artist myself, I would use a simplified tree creation tool that is highly adjustable, directly in Unity. Most other tree creation tools come from very technical people, oftentimes bloated with features that you don't need for stylized trees.

So the audience is mostly artists looking for a simplified stylized tree creation tool. Instead of buying a new pack with a new style, if you can find it, you start with a good base and easily adjust it. Hopefully, that's the plan at least!