My uro/surgeon does open RPs only. The cath comes out with the staples at 2 weeks! I can ask at my next visit, but I assume it has to do mainly with healing time for the urethra anastamosis. While one week is probably the most common time, I think when you reduce it to just a few days, you see more cases where a cath has to be put in again because of inadequate healing time or bladder spasms.
Mine came out at 2 weeks as well. That was the policy of my urologist, though I think it's pretty standard practice for
open surgeries. They also didn't discharge us from the hospital until the first bowel movement.