This is a good question: if you have a floor full of grout to remove, you could certainly accomplish it with a high speed rotary tool and this accessory and guide.  You may need multiple bits to get that accomplished.  A single bit is really designed for small repair jobs.  If you have a lot grout to remove, you could also consider using one of our oscillating tools.  That may be faster if you have greater volumes of grout to remove.