Unless they are mutually compatible (which should be the case I mean thats the whole point they changed FGems etc), meaning I can log in with my PC account onto the mobile version, and then log in back on PC later, to classify for the rewards, there is no point fretting over it.
I am not gonna make a dupe account on a mobile platform just to get those prizes, since overall I am not a fan of dupe accounts, or even playing the same game on two platforms (I only hold on Nutaku just because, but once I wont have time for it, they piss me off, the game dies, or Girls Symphony returns, I will more likely then not drop it).
Would be nice if the rewards were for all players though. Or at least they made a similar "thank you" thing for the PC users, if not handling out a 6*, then maybe something like 150 Rainbow Coins or something, which is pretty much half a choose whom you want 6*.
PS: Can anyone take a look and translate the picture I posted pretty mofu please ?