Interesting discovery about Hype Zircon 1/8 buggy diffs

[Jasper]

A few weeks ago I bought a Hype Zircon 1/8 buggy roller from www.markplaats.nl (something like ebay). I bought this chassis with the intension to use the center diff for other projects. But when I opened the rear diff housing, I saw that the ring and bevel gear were spiral cut. Just like the hotbodies lightning diffs. When I started to disassemble the diff, I saw no normal gear diff, but a planetary diff. I know that the spiral cut ring and bevel gear are nice, because of the smoothness and less stress on the drivetrain, but what is the advantage of a planetary diff over the normal gear diff?