I forgot to add that a friend of mine uses one and she was appalled that I did not use one. She doesn't even do a lot of quilting and if she does, one Q at a time and buys fabric only for the project doing - no real stash.
I agree with some of you that distractions seem to cause the most accidents - (cats are real culprits here LOL) - like briefly looking up when cutting or glancing away when running fabric thru machine and getting hit with needle! I worry more about getting a broken needle in my eye than cutting my fingers I guess - do enuf finger cutting in the kitchen!