Well, general thoughts:
-as we all know, 'fit & finish' tend to depend on the manufacturer. Let this be a disclamer...
-I've now had a bike (Triumph) with a matte painted tank for 3 seasons. I keep my bike clean(ish) and I'm mostly a fair weather rider. A bit of gravel dust, bugs and even mud, but nothing difficult to clean. A gloss paint is definitely easier to maintain, as you can use quite a force to clean it & waxing gloss paint is an easy way to make a bike look like new.
-that said, nothing wrong with my matte paint after 3 seasons. No waxing, no special products used (... let's not mention.... OK, I'll do it anyway: I've used only hand dish wash soap for cleaning
)
-not that this matters much to most, but I'll have to add that my bikes stand outside, under a light cover about 7 months per year. Temperatures varying between mighty cold to slush, lots of moisture around.... matte color does not seem to take this any worse than gloss, even without wax.
I have only a tank to take care of - I'm not 100% sure whether I would like to have as much matte painted surfaces as in a Vespa, but it should be doable.