Removing a scratch from glass this way basically involves wearing down the glass around the scratch to a depth greater than the scratch so the scratch effectively disappears. This method works, and you won't notice any distortion if the scratch is not too deep. But Bon Ami is quite coarse as far as polish goes and would require finishing the job with finer polishes until the area becomes clear again. I have used this method to polish cast resin after shaping it, first with cutting and shaping tools such as metal files, then with finer and finer grades of wet and dry paper, then buffing with a machine and cutting compound, then polishing by hand using finer compounds, until finishing with cotton and metal polish. Spectacular result, but a lot of work. Short answer, it should work if the scratch is superficial, but you will need to finish with something else.