I'd dare say that it's very important. Without the open affirmation of the teacher relating to the truths being taught, the student may not feel the importance of finding out for themselves. If the students don't have the desire to find out for themselves, they never will.
When the teacher is able to testify of the truth of a principle, such as the resurrection with conviction, that can be the difference between the student prayerfully turning to scriptures in order to seek that same inspired knowledge and not.
Unless a student learns by finding out for themselves, as an individual he or she would be building on a sandy foundation indeed.