My personal problem with the whole Epic store thing is that EA has their Origin, Ubisoft has their launcher, Acti-blizz has their launcher and then there's steam. At what point can I just have my games and not bloat my shit with their unnecessarily flashy, buggy launchers.
If Epic really wanted people to start buying from their store they'd do some kinda exclusive deals or minor discounts or in game promotional content, these methods would be honey where they're currently using vinegar. It only serves to potentially hurt developers who buy into it and their sales suffer!