It`s useful, but for whom? First, you need to know how to read the whitepaper, and more important you need to know how to check everything they wrote in the whitepaper. For checking that you need to be a developer, programmer. Many of us can`t do that, we rely on community. When I read wp, I`m interested in the idea, if I like I will invest. Technicalities are not my stronger side, for that, I look at what others have to say about it.
Bottom line is that you can`t be 100% sure in your investment, we always risk. Sometimes things go wrong even when everything looks good.