"What benefit does it give you?"
The installation of RAPID is independent of Magician in its operation; you simply need Magician to turn RAPID on or off. But so? You can eliminate Magician itself from starting at boot-up.
It has a lot of reporting, benching and tweaking features. I'm obviously going to open Magician for any issues pertaining to the Samsung SSD or its performance. And I don't need it "running in background" from the system tray otherwise.
So as far as I see -- if I can eliminate it from Startup -- it's useful to have. I'll have to check again to see if the new version is still loading at startup when I deleted it from the "Start" menu Startup folder. But there is more than one way to skin that cat . . . too . . .
I guess the overriding point of it (as to benefits) is the enabling of RAPID mode in the first place. Here's my latest benchmark -- also posted in another thread. The new version of RAPID uses more available RAM if you have 16GB, for instance, and the benchmark sequential read and write scores are increased by what seems to be a factor of 5: