Guns speed up the game - of course, it can be done as you walk, what, no, can't get a correct reading, so you have to stop. Therefore playing a round (as described below) by yourself without a gun must be faster.
I was taught to play as follows (as I posted the other day)
c)Walking up to the ball from your previous shot working out
distance, obstacles/hazards/bunkers, then decide which club to play.
By the time you have reached the ball you have selected your approach
shot then go through the final motions of re-checking ball, flag,
distance, correct stance, relaxed, final look keeping eye on the ball,
swing and hit the ball, like millions of people have done for around a
100 years.
Thank God, the art of playing golf still survives in some of use. Its a simple basic skill to master and perhaps if its speed you want, this way could be quicker too.