I think that these are processes eBay puts in place to try and make sure their platform is user friendly as most people wouldn't bother going through court, so anarchy would reign if they didn';t have some internal resolution system. Their policies/terms and conditions etc are designed to keep people happy so they will continue to frequent the site and use the service.

Nobody's policies etc can deny your ultimate legal rights though.

Online auctions are treated the same, they've just had to define when and how events such as offer and acceptance etc take place, same things for communication through email etc too now that a lot of negotiations are done via email rather than post.