I agree that in any profession where you will be making presentations, knowledge of PowerPoint is a pretty basic necessity. I think we live in a time when we can no longer get away with making presentations without a visual aid.
When I was in college from 1999-2003 about half of my professors enhanced their lectures with PowerPoint. I imagine that number is far higher now. Even out of a classroom or boardroom, you see PowerPoint in advertising, church services, and graduation programs. It is a versatile program that allows for the addition of a visual to anything. The possibilities for its use and importance are pretty endless.
It really depends a lot on what you are going to do with your life. But Powerpoint (or something like it that might come around in the future) is important for a lot of professions.
Teachers, of course, need to use Powerpoint quite a bit. People in business and law need to use it when the make presentations, for example. I understand that even the military uses Powerpoint extensively. So any profession in which you are going to be presenting ideas to people is likely to require you to be proficient in Powerpoint.