I can't remember exactly what they said. I suspect the tutor was trying to suggest that doing self-directed briefs would be a better option, but the person i spoke to said they were quite dismissive and did the D&AD brief anyway without any advice from their tutors.
More generally, a lot of graphic design academics really don't like D&AD New Blood briefs. Partly because of their commercial focus, believing University is for personal expression and that graphic design (quite rightly) isn't just a tool to sell stuff to people. Partly because of the nature of the briefs in recent years, being at the mercy of whatever sponsors D&AD can get.
However, for the vast majority of students/graduates/professionals - graphic design is a commercial profession, and giving D&AD briefs a go is a really good way of working on realistic projects, and testing yourself against the best students from around the world.
With a few exceptions like CSM, all the good courses get their students to do competition briefs (such as ISTD) so it is a good way to compare courses (particularly when you compare award wins to cohort size) but for graphic design at least - D&AD isn't the barometer it used to be. It's still the gold standard in ad land though.