The path of the cb with draw can be determined just as precisely as with follow. you just have to know how to do it.
Check out Dr. Dave's material.
The problem is that it takes a lot of practice to get the cue ball to arrive at the object ball with the desired quality of draw, where quality is defined as the amount of draw in proportion to the speed of the cue ball. In the case of follow, if the cue ball is rolling smoothly on the cloth, the quality of the follow is extremely consistent without any effort from the player. (It is the quality of the draw/follow that determines the carom angle.)
On a half-ball follow shot, the deflection angle of the cue ball is 35 degrees within a degree even for beginners. On a half-ball draw shot the deflection angle is 90 degrees only if you manage to get the cue ball to arrive at the object ball with just the right amount of (lively) draw. Beginners will not be able to control that angle within 15 degrees for a range of conditions.
Consider breaking out a cluster. Would you rather have a stun or follow shot to do it or would you rather have a draw shot? Which is more likely to land on the ball you want to hit and on the side of the ball you want to hit?