You can still adjust hop with the r-hop. It isn't a fixed hop. I like to sand my r-hop down so it's flush with the barrel so when hop is turned completely off the bb does not touch it.
What the r-hop does is give a longer contact area to the bb, letting it gain backspin slower than than the regular bucking mound. Because it gets backspin slower and more steady, it is more stable and doesn't vibrate in the air as much. Because it doesn't vibrate as much in the air, it is more stable, which equates to more consistent shots and a flatter trajectory.
What the r-hop does is give a longer contact area to the bb, letting it gain backspin slower than than the regular bucking mound. Because it gets backspin slower and more steady, it is more stable and doesn't vibrate in the air as much. Because it doesn't vibrate as much in the air, it is more stable, which equates to more consistent shots and a flatter trajectory.