Potential HOA and permit issues. Making it look nice 100% means cutting the lines and dealing with that. The siding/walls is the area are a complication. Honestly it doesn't really matter what my reasoning is. If there's something unsafe about a temporary install I'm all ears. It seems like a floor unit isn't going to really be much cheaper (even factoring in tool rental/purchase). The available window isn't super wide so I might have trouble finding a window unit that is a heatpump that will fit.What is so hard about installing a minisplit properly so you can sell it with the house? Drill the holes, install it nicely, be done.
How do you know you will need a minisplit when you move, anyway?
If I happen to move to a place with absolutely perfect HVAC/minisplit worst case I keep the unit as a spare, or add it to the garage/workspace. Around here AC/minisplit are not common so thats not likely anyways.