points you mentioned are good, but privacy does not necessarily mean decentralization, and managing a decentralized market will be more difficult than a central market. We value privacy, but it is difficult to find a lot of interest and success in a decentralized market, as the user will need to download the software and manage it, and the process will be slower than central services, and risk Restrictions are lower, especially if all goods are legal.
I understand your arguments.
Though, in the case of a fully smart-contracts powered marketplace, users would not need to install any client. The market would theoretically be accessible from your computer terminal if you'd like to. All that would be required to interact would be to know the 42 contract's address characters, and an internet connection.
In practice, user-friendly frontends could emerged and be hosted on traditional URLs to provide a more intuitive and familiar interface for users.
Actually, an infinite number of UIs may be developed, all connected to the same underlying marketplace. This would make the market highly modular, and accessible to a very broad audience.
About privacy, anyone could order a thousand times, each time with a new identity. On such a market, the "identity" would only be defined by your key pair.
Also, none of your personal information, such as your phone number or last name, would ever end up on leakbase.io or any other shady site.
From my perspective, this represents the pinnacle of peer-to-peer technology, and I find the idea very appealing.