There were a few reasons I didn’t go with Bob’s knobs.
1. I have long arms but I still don’t think I’d be able to reach them while looking through the eyepiece on this scope.
2. Some people say they don’t hold collimation quite as well as normal screws. Not much in that one possibly.
3. I suffer many afflictions. A couple being perfectionism, and a severe case of OCD. Having the knobs would just make it far too tempting to fiddle all the time, and like you say Paul, going near the corrector with a sharp instrument is not much fun. Very scary actually. Kinda works the same way as that stuff people paint on their fingernails to help stop biting them. If you don’t like it, you’re less likely to do it.