Maybe, but I’ve used wax on glass (windshield) before, with not an issue.My guess is that the "polish" that you've been using contains a very, very mild abrasive in order to clean up the bottom of the discs. I would definitely NOT use this on an iPhone as it is GLASS and not PLASTIC like CD's, DVD's, and the like.
I use a hard screen protector and wipe it on my jeans...
Maybe, but I’ve used wax on glass (windshield) before, with not an issue.