Indeed it's surprising to see how abundant trichomes on plants are, they do even serve mutliple different functions, such as to keep the rH right near the stomatas a bit higher and throttle the windsheer down (others develop defensive toxins in them, some plants use them to regulate how much water can stay on a leaf...) so they are all a part of a plants ability to adapt to the ambient environmental conditions. A way to being able to keep stomatas more open and not to loose that much water