I can't wrap my head around this one either. Yes, Steam UX is horrible, every action takes 2 seconds to complete, even opening the home page takes 2 seconds when Steam is already running. They haven't even bothered to put up a loading spinner, it's just a black screen. And yet, somehow, Epic is even worse. Doing anything in Epic you have to look at black screen for like 5-10 seconds, and you never know when it has crashed versus when it's eventually going to finish doing whatever thing it was doing for 10 seconds.
But the absolute worst thing about Epic Games Store is that it steals 5% of my CPU cycles whenever it's running. That's right, when I'm playing a game I purchased on Epic, the game runs 5% worse (assuming it's CPU bottlenecked) because Epic Games Store needs 5% of my CPU to do nothing, all the time.