This is a great question. If it's not neccessary to shoot fast, you should take advantage of the time to optimize set-up, read wind, etc. Also, if you are shooting in volume, a slower rate will keep your barrel from overheating. I think increasing shooting speed comes with practice, as is the case with your buddy. It will develop naturally, and at a pace that matches your proficiency. I think that developing accuracy should be a priority over speed. I personally find the skill to shoot fast to be an advantage. In long range competition, where strings are timed, you can take advantage of a wind, or favorable mirage condition. Being primarily a whitetail hunter, I have had numerous situations where time has been a factor, The big guys don't hang around, particularly during the rut. Add this aspect to same need to at tmes take advantage of wind, or mirage conditions, the ability to get an accurate shot off in a small time window can be a major factor in making the kill. It's for this same reason that I switched to the G7 rangefinder
which very effectively cut out a few steps in determining scope setting.IMHO.