Stumps are definitely large causes for concern. Although not quite on the level of hazard when compared with a tree that could fall, they still pose potential risks.
A few reasons you may need or want stump grinding provided on your property:
1) Unsightly
2) Safety hazard ( could trip or fall over a stump if not seen )
3) You have to mow your lawn around them, mowing over them could destroy you blades.
4) They attract unwanted pests and critters including bees, termites, ants and water bugs.
5) Landscaping designs
6) Construction
7) Plant another tree