We are currently an MVP, not even alpha quality. Some form of decentralized IDs is high on our TODO list, but we had to start somewhere...

We considered Twitter is a good start, since we need some way for people to recognize others (an informal reputation sort of thing). We'll leave that behind eventually, Twitter will become one of the various identities you can link to your account, KeyBase-style, and it will all be optional.

The whole thing is actually built to be decentralized and unstoppable. While we run the instance at plebeian.market for you, you can run your own instance, with your own modifications to the code (which is GPL), hosting any auctions you care about (whether antiques or used cars), in which case you can have your own rules.