Full stump excavation is a far bigger ticket than grinding, and a company that wanted to could talk most homeowners into it — roots sound menacing, 'complete' sounds thorough, and nobody can see underground to check. The truth is less dramatic: a root system without leaves is dead wood quietly becoming soil. Grinding removes the part that was ever going to bother you; the ground handles the rest for free.
The cases that justify excavation are real and we name them plainly: construction on the stump's footprint, where settling buried wood would undermine a slab, and replanting in the same hole, where old grindings starve the newcomer. If yours is one, we will tell you — and also that excavation is heavy-equipment work for an excavation contractor, not a line we pad onto a tree invoice.
What we ask in return for the cheaper recommendation is that you hear the unglamorous truth about grinding: the spot settles. Grindings lose volume, the fill dips over a year or two, and a bag of topsoil and seed finish the story. Companies that skip that sentence get the angry October callback. We would rather say it in the driveway at quote time.