Do I want one? What do you use them for? (Seemingly) decent one on offer @ Screwfix, comes with a wire brush which is handy apparently!

This framebuilder uses one for polishing parts.

When I give up my mundane life to be an artisan framebuilder 😀 I shall use one to craft lovely dropouts.

I could use one for sharpening knives, lawnmower blades and axes. cleaning up wood carvings, spoons that I might one day make.

Good for finishing off outer cable ends.

One word. Goggles.
But yes, useful.

Depends. I only use mine for sharpening drill bits and lathe tools. Pretty much essential for those tasks but not really useful otherwise.

A belt-grinder with a grinding wheel on the other end may well be more versatile.