I've been growing for over 25 years and have NEVER had to mist a plant..... so, no it does not benefit the plant in any way, only the fertilizer manufacturers. As plants grow older, their roots lose some of their ability to absorb well. But if you've added the correct bacteria, enzymes, etc.- you'll be fine. It's only necessary to mildly spray when you have some deficiencies- but at 1/4 strength and maybe once every couple of days. Make sure you rinse the plant off too to remove the residue. Definitely don't mist when your developing buds or your inviting mold, etc.