Traditionally used to sharpen woodworking chisels.
It appears to be the same little Scheppach machine that Hare & Forbes sells for $220 plus delivery.
Unlike a grinder, which will overheat the tiny edge of a chisel and soften the steel, the water bath keeps the wheel, and edge of the chisel, cool.
If you are patient, could also sharpen blunt HSS lathe tools, engineer's scribes, drill bits et c. Only has a little 150W motor though, so if your chisel has chips out of it from hitting too many nails, you will need to be very patient with this. (probably no good for metalworking cold chisels :-)
Will it sharpen my katana?