It is said metal utensils scrape teflon coated non-stick pans and should not be used on them. All sources I found say just that. But when my metal utensil doesn't have sharp edges and I am not pressing on it with more strength than a wooden one, why should I use a wooden one over a metal one? Is there any chemical or other reason beside scraping the coating with the sharp metal edges? Not all metal tools are sharp.
Metal is a lot harder than wood, which means when it hits another surface, it won't deform on a microscopic level the way wood does. This means that, while a wood utensil rubbing against a nonstick pan will get compressed a bit, the metal utensil will rather cause the nonstick surface to get compressed, which results in scratches and other damage to the nonstick surface. You can use a fairly large amount of pressure with a wooden utensil and still not damage the nonstick coating, since the wood is not nearly as hard as the coating. However, metal utensils don't need to do much more than brush the surface of some coatings to scratch them, since they are much harder.
For this reason, metal utensils don't have to be very sharp in order to scratch a softer surface. Think metal balls rolling on a glass/plastic surface: they will scratch and scuff the surface, even though they are not "sharp" at all.