The way I’ve been using it for a few years is that most of my machines can see each other and I have a shared folder and versioning setup. As I add things they move between the different machines and once an additional machine has it it is available to the others until everything is in sync

You can definitely do chain topologies which are useful for certain things with a single source of truth

TIOBE merely measures the number of questions asked about a particular language online, which is obviously not exactly realistic metric but people for some reason love to spout it

As a note, I believe that syncthing will actually scale up with more nodes as they will all share with each other if they know each other. If you’re doing this 1 to many then this is not the case of course.