I am an engineer for more than 12 years. I think I have a reasonably good idea of how a blockchain works.

I have no idea how these two projects are supposed to work. Who is supposed to use this if there isn't even a concise description of the product?

Judging by their Twitter accounts both of these companies have been around since 2017. How many active users do they have?

https://www.youtube.com/watch?v=hf-Op-1peZI for less formal overview https://www.thetatoken.org/ contains white papers if you want the technicals.

I think he's asking if anyone has found this useful in 5 years? Are there actual customers or is this just an idea?

A couple of things. First these are companies that are building up. They are not fully instituted. Second they have many partners that are helping them build out. As far as customers, yes both THETA and VET have customers....including some .gov customers.