But is 50% off really 50% or isn't it only marketing? Here (and maybe also at Unity asset store) I can very easily change prices of all my products. So if you see 50% off it doesn't have to mean really 50%, because 50% is so huge portion of revenue that artist are thinking about tricking.
With 30% off there is no big reason make such a tricks so it is more fair for both sites - artists and sellers. And you will get REALLY discounted items.