1) I agree with what you shared mostly, and I love SyncThing!
2) I think you over exaggerated how difficult DropBox is. For typical users, just selecting the defaults is good enough, and let's be honest DP is pretty rock solid.
3) I think you WAY under exaggerated how technical setting up SyncThing is .. for non-technical users. It was a stretch for me, it would be a nightmare for most of my users.
4) If ST is reliable (I am testing now), I can see some place I would like to use it.
Take care! Gary