Stealth. Ease of installation. My other options would be to run a window unit in a small room next to it. Id have to seal that off and add some intake holes to the grow room and hope it pulls in enough cool air through the negative pressure... For smell of course.
I like the idea of the split for odor reasons and then Maybe i could install it outside this summer...
Well to move the unit later you will need a refrigerant recovery pump and a recovery cylinder. A set of refrigerant scales to weigh in the charge after you move the unit.
I have seen some units that have a dip switch pump down mode setting and you close the high side refrigerant valve on the condenser and the dip switches over ride the unit and it will pump itself down, pulling all the refrigerant from the low side evaporator loop back into the unit, watch the gauge manifold and when you just start to pull a vacuum on the low side then you close the low side valve and all the refrigerant is back in the condenser unit like it was from the factory so you can then disconnect the line set and move it. Still it's better to recover the refrigerant and weigh out the charge, see if you lost any of the factory charge. Then you can weigh in a full charge after moving the unit, pressure testing the line set with nitrogen and pulling a hard vacuum.
The condenser unit will likely put out more heat than you expect and if you cook the unit you will be looking to replace the compressor within a year or two.
I knew a dude back in Missouri that was trying to do something similar with a brand new big ass 25,000 btu/hr window AC unit and had the condenser side stuck thru the wall into another unused room, so it would not freeze up in the winter and so it would be stealth. That room was connected to a blower and he was pulling heat out of there for sure, pumping it outside with an 8 inch centrifugal fan, but not enough heat was being moved out of that room, it was always hot as hell in there, in the 90's all the time. That unit only ran for about 5 or 6 months before the compressor gave out.