I am fairly certain that "Pixel Snapping" is required, otherwise you would have pixel movement that is much smoother than 84x48.
Edit: Upscaling is superior in my opinion, I made a short video demonstrating the differences.
I made a short video demonstrating the differences.
The squares of the gray grid in the background are 1px each, 84x48 upscaled to 840x480. The left side is the scene view, the right one the game view.