I don't think I've ever heard that cannabis was a treatment for PTSD let alone a good one.

Is this paper trying to confuse people about psilocybin?

How many veterans do you know? How many veterans that you know use cannabis to treat their PTS? I guess I might be living in a bubble but there are plenty of videos of veterans and others talking about how exactly it is that they use cannabis for PTS. I recommend watching some.