I asure you some publishers/developers here know about it but aren't there.
"because nobody knows about it" well now you know.
"the site's UI is atrocious" Is that more important than the free speech principle?
First, you or I, we don't matter. We're not enough to matter. Hell, the entire population of this forum probably isn't enough to matter, except to very small publishers. It's the hellish catch-22 of trying to start up something like this - you need a user base and a publisher base, and both need the other to really make it work. Publishers won't bother selling if there is no market, and you won't have a market unless there are publishers selling product people want to buy.
Second, is the UI more important than the principles driving the website? Bluntly, yes. If I can't find stuff on the site without frustration, I'm going to give up in frustration. I don't
need anything on that website. It's not like grocery shopping, where I've gotta hold my nose and do it, buying some new gaming PDFs? Purely a luxury.
It's no different than went wokeists try to do their alternative "totally-not-capitalism-guys-trust-us-but-buy-our-shit" businesses and they have all sorts of problems as a result of being fucking braindead wokeists. Running a business is hard, but you gotta do it right, or you will,
like the majority of small businesses, fail. Ideology will only carry you so far.
Flippin' hell, I'm not saying I want them to fail. You come here, you ask why people aren't using it, I offer a couple of quick suggestions, and you respond with derision ("It's not important!") and outright hostility (Accusing people of being bootlickers for not using your preferred storefront). Don't ask the question next time.
Its the same reason (barring exceptions like "The Chosen" where those involved actually applied the actual principles of dramatic writing and had good actors and production values) that no one really watches Christian entertainment; most of it is just BAD! Badly written, badly acted, badly filmed. If you are prone to second-hand embarrassment, it will almost invariably trigger it. Zeal without talent is worse than nothing at all.
"Can't you see you're not making Christianity better, you're just making Rock-and-Roll worse?"
-Hank Hill, modern day prophet.