As a microbiologist and a stamp collector, I'm curious why a stamp (or coin) collector would need a 100X magnification.

My research microscope is capable of optical magnifications of 100, 200, 440, and 970X, but I never need it for examining stamps.
That's just WAY more magnification than I can use. Instead, I use 2X, 4X, and 7X hand lenses and find those adequate. I would think that 20X would be the absolute maximum I could ever possibly need. Remember that as magnification increases, the field of view decreases (you can only see a much smaller part of what you're looking at).