I like the idea of the site but as others have said, the things that they want to buy are mostly unavailable.
I remember there was another site (can't remember the name) with a similar concept like yours but it didn't offer anything for sale. Instead the site allowed buyers to post a link to the item they wanted to buy from amazon/ebay/wherever and then the site would take their shipping address and buy it for them. The site paid cash but the buyer paid in crypto.
That model probably doesn't encourage the kind of crypto adoption you are looking for but at least your customers get to buy whatever they want using crypto. Maybe you can start off doing this until you get a decent number of actual merchants who are willing to accept crypto for their goods/services.