After reading through the comments, I think it would be wise to actually ask individuals who play and buy games, but do not make them; if they were going to check out a game from outside the steam store front, what would it take? Try and focus on the individuals who are avoidant of more independent store fronts and try to figure out why they might feel uncomfortable browsing and purchasing from a more independent source.
I think I posted four games on itch before actually purchasing a game, because I didn't quite know what the payment processing was... It turns out it was just payPal. Most people can do that, but keep in mind that GooglePlay wants a "google wallet" and there are a ton of ways to pay for things online.
I think there is also the concept of "perceived quality"... It is assumed that there is a form of quality checking on Steam, but terrible games exist on their, so how bad must the games that do not get on steam must be? A customer doesn't know the process of what a developer does to get on steam, so they just assume it's all quality control.
When I tried your site; I got an error the second I clicked on it... is it mean for mobile browsers? I didn't check the browsers development terminal because I was trying to get the non-developer experience, and it's quite the turn off. I'm going to assume that you're just starting up and provide some advice that you should feel comfortable dismissing (I've never sold a game).
Once you set up a payment system, it's quite common to take around 10 to 30 percents of each sale, no matter what you settle on; people will complain, but use a percentage of that income to source connections with social media personalities related to specific genres. Set up game jams and so on. Educate people on the payment system and try to push an anti-DRM mentality. Don't waste your time on an external downloadable storefront, focus on convenience; "make an account, we'll take care of the rest", then you can advertise; "we support indie developers".
If you try to build a store front around the concerns of indie developers; you will get a store front for indie developers, selling to other indie developers, but if you ask the actual market; you might build a functional market.
To directly answer the last part of your post; yeah, I'll post my games anywhere that will have me, but I think you could probably have a slightly higher bar than that. You could have developers proudly posting the first link on their advertisement to your site.