Material removal covers just about everything other than sawing.
The oscillating tool has sharp knives, often called scrapers, which slice through material too soft to cut with a saw blade.
Digging material out of slots is a unique challenge and the oscillating tool has special blades just for this task.
Of course Grinding and Sanding is our most common of material removal tasks.
The oscillating tool does each of these task in its own unique way, even distinguishing its sanding functions from those of an orbital sander.