its true, i think it is kind of strange as well to not have a whitepaper when a project is launched.. but there are legit projects that release a whitepaper later on, an example would be deviant coin a.o.

though a lot of you are right i agree that a whitepaper makes it clear for people what the project is about so people understand what they're investing in, a roadmap is also not unnecessary and gives a vision of what and how they will achieve things.