Ok, maybe I missed something, but can someone explain to me why a decentralized marketplace is an important thing to have? Apart from the fact that you can pay

Ok, maybe I missed something, but can someone explain to me why a decentralized marketplace is an important thing to have? Apart from the fact that you can pay there with Bitcoin (which you can also do at other e-commerce stores), it seems similar to Shopify from a merchant's (or vendor in OB slang) perspective. So I get that makes it simpler to use for products that are not simple to get otherwise (e.g. drugs), because of censorship and outdated governing (I know you can in theory buy and sell anything, but I just downloaded it and searched around and most products were either tests products, or drugs and sex-related), but I don't see what other benefits there are. I mean most people who want to sell stuff over the internet struggle with the fact that nobody wants to actually buy their stuff - the fees or monthly costs don't seem to be the reason for the failure of these shops. Furthermore I would guess most people go to a central place like Amazon, because they have some kind of reputation (although expectations are getting lower) and their support ("where's my package") is quite OK (from a customer's perspective) - although the customers could go to small indie shops and buy stuff there. Outside of products and services that are illegal to sell or buy because of jurisdictions (if these jurisdictions make sense is an orthogonal question I would say) what is the additional benefit for buyers and sellers?