Here in Vietnam nearly all ACs are these minisplit type. It costs about 500,000VND ($19) to get one serviced, including replacement coolant. It's cheap enough that I get it done at least once or twice a year for all units (the coolant doesn't always need replacing but I get it cleaned and serviced).
I know the US and Vietnamese economies are very different, but something doesn't add up there.
Minisplit AC units are not very popular in the US. The US mainly uses either central air conditioning units or all in one AC units that are designed to be installed in a window. The window units are cheap, but inefficient. The central units are more efficient, but very expensive. Minisplit units are more expensive than window units (by probably a factor of 10), but are more efficient than either. I suspect most people in the US do not know that minisplit units are even an option.
In my home, I recently had a heat pump unit replace my central A/C with some minisplits that connected to the exterior unit installed in the basement. The entire setup cost as much as it originally cost to install the central A/C, despite parts of the central A/C being reused.
Note that in the US, what we call air conditioners only support cooling and not heating. When they support both, we call them heat pumps despite that being the scientific name which applies to the cooling only units too.
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.
That said, I was replying to someone from Vietnam. Assuming that things in Vietnam are similar to China and Japan, people will only heat or cool the specific rooms that they are using, rather than heating or cooling everything like how many Americans do things. Those in the US who cannot afford to heat or cool everything, who are likely very underrepresented here, would be those using window units, since they are cheap upfront. A minisplit would be cheaper over the long term, but the high upfront cost dissuades people in thing market from even looking at them.
Finally, I had Fujitsu minisplit units installed in my basement two years ago. They are far more aesthetically pleasing than window A/C units.