They're a good soil amendment, adding tilth & attracting earthworms (organic tillers).

there is controverse opinion about using it as a slug repellent. I used some and thought it worked. A friend of mine used lots, it was an awfully wet season and all the mean slugs just sailed over it.

As it is pretty acidic you can pamper a Rhododendron with it.

Used grounds are actually fairly close to neutral in pH. Starbucks did an analysis of pH and nutrients. There is a LOT of discussion along these lines in the soil and compost forum.

One thing to be aware of is that they seem to impede seed germination, unless composted. They also cake and repel water if applied too heavily to the soil surface. I usually sprinkle them on established plantings, or mix them with soil that will be fallow for a few weeks. If/when you put your garden to bed in fall with chopped leaves, they make a good addition to those. Earthworms love them.

Hepatica

We throw ours into the compost bin.

I save coffee grounds at home, at church, and at work,then let them dry in the sun, and just sprinkle around the garden. They are suppose to be good in asparagus beds so that is where most are going.