I find it the same kind of motivational teaching as saying that human birth is rare, meeting the Dharma is rare, etc. The point is to go study and practise, otherwise you're just wasting your time.
I'm also inclined see this as a pedagogical tool.
However, human birth seems rare if we compare the number of humans with the number of non-human animals on this planet and we assume that we can be reborn as an animal. If from the human group we compare those who practice Vajrayana with those who don't, getting both conditions, being human and practicing Vajrayana (or any other form of Buddhism) seems rare. So I guess it's both a pedagogical artifact with some reality from a Buddhist perspective in it.
However, the point is as you very well stated "to go study and practise, otherwise you're just wasting your time" and this tool just cautions us that the opportunity for doing it is now. If we let if pass, who knows?