I would say Yes. Epic provides a Powerful Development Platform for FREE and provides the Unreal Marketplace (UMP) via Launcher & Web to distribute supplemental products. The UMP is the only online store I trust for UnrealEngine related Products due to the curation.
I’m also looking at this from a Content Creator’s position as intend to publish products of my own to the UMP. I’m including the 30% split in my Pricepoint/Retail Markup to set price accordingly. With Sales, a 30% split is negated by Sale discounts (some which are upto 80%). My strategy is to diversify my distribution and aggressively advertise my products.