It's pretty much exactly how it was in the book. Harry needed to know that he had to die. Snape meant tell him but didn't get a chance. That is why, in the Shrieking Shack, Snape was almost frantic begging Voldemort to let him go find Harry. The world would have been screwed over if Harry didn't happen to be there when Snape died and got his memories.

It also made Voldemort sure that the wand worked for him... but he was wrong