Web 3.0 is of course not a scam. Also, I couldn't find the opportunity to review the website you suggested. I don't want to comment about it.
To briefly explain Web 3.0, the Internet world initially only allowed its users to read. We used to read simple html news sites. Then, we said hello to Web 2.0 with interactive social media sites. I don't need to tell you what we are going through in this world. A simple example:
https://en.wikipedia.org/wiki/Facebook%E2%80%93Cambridge_Analytica_data_scandal Today, Web 2.0 centralized applications that use our data are being replaced by decentralized applications with Web 3.0 technology. For example, the words we type in the search bar will no longer be shown to us as advertisements or if they are shown to us as advertisements, we will earn money in return.