People don't realize that many publishers/developers have raised prices on EGS in the past during the sales because Epic store-wide coupons were applied without permission from the publishers, essentially dictating the value their games are sold at on the store. Stay classy, Epic.
When Epic is covering the cost of the coupons, what does it matter to the devs/publishers? And how is it different from those store-wide $5 Steam sale coupons, which can mostly be acquired by simply doing a bunch of Steam activities? Does Valve seek permission from every publisher in this regard? TW3 at $14.99 on sale would cost $10 to someone with a Steam sale coupon.
And there's no lower limit on these Steam coupons either. If a game is on sale for $5, getting it via the coupon makes it free. How's that for dictating the value of someone's game?
Similarly, in the console space, both Sony and MS have also offered discount codes that can be applied to further lower prices on games during their respective store sales. They couldn't possibly have sought permission from all publishers/devs selling games on their stores. They simply bear the cost of the additional discount. This has been a standard practice for years.