Most whitepapers are trash. Lot of buzzwords about disrupting old-fashioned industries, lot of unnecessary padding about basic crypto stuff (what is blockchain, how Bitcoin has changed the world and bullshit like that) and lot unnecessary neologisms trying to impress technologically less knowledgeable people. What you should be looking for is at least semi-detailed technical explanation coupled with detailed business plan in any shape or form. It could be in the form Wiki or documentation hosted on Github or even whitepaper. It doesn't matter as long as it contains detailed description of project itself and not some general mumbo-jumbo about utility of blockchains.
I do agree that most whitepapers are thrash. Remember, they are written by marketers most of the time. But I still think a whitepaper is a very important document. Its more like a business plan. And a potential investor I always want to see it and analyse it. Any skilled person will be able to see through the BS in these whitepapers. Now when a project can't even write a whitepaper, anyone should worry. However if you do see a project with a good and convincing whitepaper don't stop there. Follow them on social media, review their code on Github. If you are not a programmer you can still see if there is any development happening.
