I think it sucks but I don’t have an issue with it. If Epic is the publisher and they choose to publish only on their own store then that’s their decision. It’s what every publisher, including Valve, does. To me this usually means it’s a game I won’t play and that’s not a problem because I have so many games to play, I won’t miss a handful of games.
However I will buy World of Goo 2 if for no other reason than the fact that I pirated the first game when I was poor.