Not a whole house mini split but we have an old addition that goes 90 degrees from the main part of the house. The ductwork from that side doesn’t get to the addition at all. So we did a mini split on the addition and shut the air flow off to that side. It works but the mini split has its own little issues. I had a mouse crawl up the lines from outside and go into the mini split unit and chewed up the room temp sensor. So it wouldn’t heat proper. The screens on the unit get plugged fairly easy and need cleaned every 2 weeks or so. The guys that installed it also didn’t get the drain part pointed downhill enough and sometimes it’ll start dripping water out the unit and make a mess inside. I’ve got it fixed for the leaking but it should have been done right the first time. I don’t know your setup but unless it was a perfect fit  for your situation, I would not do one for a whole house. Plus it’s kind of an eye sore, having a unit in every room. Just my opinion.