When I installed AC in my former Bay Area home, I would have needed multiple mini split units to cover 1200sq ft, with questions about how many you could have on at once to still get the right performance. I went with a single central air unit instead.
It also (at the time at least) didn't come with a centralized thermostat, which meant managing each room individually (that would've been fine with me, personally, but it's a drawback for lots of people).
On top of that, many (if not most) mini split units are also somewhat aesthetically displeasing.
In my new home (on a different continent), I have mini splits. I'm somewhat satisfied with them, at best. I'd still prefer central air but it's not a thing for residential homes here.