I don't think marsa, as they're called where I'm from, are the same thing as described here. At least in my home country, they serve routes that don't get enough traffic for a large bus, so they have their own numbers and routes. Usually you would get one if you're going to a small village in the countryside or similar.

Hmm; not sure then. I remember riding one of these in Odesa about a decade ago, from the airport to the city (presumably a route that would be busy enough to have a bus line.)

They operate in post-soviet cities too, especially between microdistricts.

Well I was indeed thinking of marshrutkas, at least as a saw and used them (many) years ago.