Cable needs to be protected if it is subject to damage. And that is a subjective decision (by the AHJ).
Unfortunately no, this is not just bringing it down through the floor to the basement. To get to the basement, I need to bring it all the way across to the other side of the garage. There is no type of attic space above that I could use either. So in any scenario, if I wanted to hide this behind drywall, I would need to cut into and drill a bunch of studs. Not worth it for a garage in my opinion.Can you fish the wire down the inside of the wall in the garage? Even if you had to cut the sheetrock and replace it, it will look better than conduit.