I think the decentralized but moderated review network is the most important part. I like the idea of local shop keepers with specialized knowledge (I’m thinking of my local goto kitchen store) or just online experts (like the folks at whathifi). I like to research a bit (a lot really) before I decide what to buy and a resource like this would be invaluable. Finding it locally after deciding what to buy can be an issue (especially if you are not in the US), but this aspect could be separate, as is shipping.