The difference is the perceived action of the cb vs. the anticipated action of the cb. Meaning that if the cb is hit in the same spot at the same speed with both types of stroke, there will be no difference whatsoever in the action of the cb.
The problem arises with the poke stroke. Some think a poke stroke is any stroke that utilizes a short backswing. Such as Allen Hopkins stroke. One hears all the time that Hopkins has a poke stroke, but still can get good action on the ball. That is just not true. Hopkins has a good stroke, just a short backswing.
When one utilizes a poke stroke, the cue is invariably slowing down on the way to the cb. And, usually stops with little followthrough. The followthrough happens long after the cb is gone due to the cue slowing on the way to the cb. This results in not hitting the cb at the desired speed, thereby not getting the required action ( spin) on the cb.
A poke stroke usually happens because one is trying to hit the cb with the tip of the cue. It's only natural that one slows down as the tip actually approaches the cb, even though it can not really be felt.
During a good stroke, the cue accelerates to a given speed, then maintains that speed right to contact. The contact of the cb is what slows the cue down, nothing else. And, then, the cue is allowed to come to it's natural finish ahead of where the cb was. Be that several inches or even up to a foot or more on some shots.
Using a good stroke, one can learn to anticipate what speed gives what kind of spin the cb. And therefore become quite adept at controlling the cb's speed and spin for position play.
Using a good stroke, one does not strive to hit the cb at all. Instead, the goal is to shoot right through the space that the cb happens to be occupying.