punching through a window with bare hands (with or without this silly ring) is likely to result in additional casualties on scene - namely your hand will now need to be bandaged and you will probably also violate standard BSI protocols in the process.

OTOH if you are walking alone in an urban environment late at night then something like this might be as handy as having your keys poke out through your closed fist, just way COOLER and more expensive. Heck buy 8 or 10 of them and wear them right along with your tattoos and black nail paint and the lag bolt through your nose.