All you have to do is pull up some billiards on youtube. In pool you use a whole slue of strokes from a short nips maybe pulling the cueball back 4 inches to a length of the table draw shot or stop shot to a slow roll.
If you are on a non heated average speed billiard table you may be whacking the cue ball all over the place with little finesse after a while. I can only go by personal experience and owning a pool room with billiards tables watching players play. This is not meant to be a debate I can only go by my own observations.
Here is an example of Sang Lee
http://www.youtube.com/watch?v=XkoxT63v32c
His billiards stroke just does not relate to playing pool at all. He was the worst pool player you ever saw for a guy who was a world champion in another cue sport. Billiard players just seem to have this short polk stroke an most shots. Now pool players who play billiards a bit seem to just use their pool stroke at first, but over time they change and this change it what in my opinion becomes detrimental to their pool game.
In fact, the object of what they are trying to accomplish on the billiard table is completely different then on a pool table. They are different games. I do believe in playing all games from pool to golf, snooker to billiards to banks and so on. I like all table games. I have always been more impressed with all-around-players then specialists. About the billiards stroke, I am just speaking clinically.
I could be wrong.