Coffee grounds are not worthless. They can be used in a couple of ways. The first way is to mix some milk with the coffee grounds and use as a face mask and exfoliate skin. It is a nice body scrub this way too. You can let the milk and coffee grounds sit on the skin for 10 minutes and wash it off. It makes your skin look nice. I went to an aesthetician after I tried it and she wished my skin looked that good. She wished that she had as good as skin.
Another use of coffee grounds is to use it in compost. Using coffee grounds for compost is good for plants. It helps the soil. Too much is bad for the earthworm, however. Too much coffee grounds is too acidic for lots of worms. But it is very good for blueberries. Blueberries love coffee grounds. You can also grow mushrooms with coffee grounds. it is very good for certain kinds of mushrooms. They love it. It is also good for improving the soil.