Aura Plates are for hosting Hyperion, so that you can get your hands on those Aura Cubes -> Photon Crystals without paying a fuckton Deflection Steel. Currently hosting Hyperion is free, will change in a couple of weeks.
And yeah, the rewards in this suck ass. I'm still gonna keep doing it, but I'm not surprised if others won't. I just worry that within a week, I won't be able to complete Hyperion raids due to lack of people joining. If that happens, hopefully after nerfs I can keep farming...