Getting to the gun while riding is also a non issue. The gun is for the rest of the time, and I am not going to go digging around in my bags at every gas station or diner to fish out a pistol in the parking lot so I can stow it on my person and then reverse the process. This is a recipe for unwanted attention. Concealed is concealed.
This is the biggest factor for me. I put it on and forget about it, just like I would if it was on my belt. I am not moving it around from place to place or unholstering/holstering every time I stop and walk away from the bike.