The difference between an amateur and a professional
There are some examples of this same effect that are more common. Look at, for instance, the slightly-off-angle stop shot.
http://www.youtube.com/watch?v=UZAqHno_Kr4
That's useful and I would recommend always going "towards" a rail when shooting this shot. Of course this is something I would suggest as much as possible, and is more about "locating zones."
A great drill I use when preparing for a "game" is going an extra rail EVERY TIME. Buddy Hall told me how he calculated his Zones for position and simply illustrated "one is better than none, two is better than one and three is better than two." For pin point position it's best to either go to an extra rail or at least towards an exact spot on one.
This doesn't mean if you could "stop your ball" you should go one rail instead, it's just how to look for your biggest zone for maximum "margin of error." When looking for zones you complete the cue ball's "path line" to the rail or you can't see the potential "trouble spots."
This is best understood when you become completely familiar with the "natural" angles using a consistent "no side spin" cue ball.
Once you completely master the "no side-spin shot," then you are able to truly use it as a relative "index" for every situation. As you know exactly what hitting the cue ball slightly inside the vertical axis will do, you start to "real eyes" that you don't really "need" side spin.
Then {after this is experienced} you can use side spin because you want to, not because you think you "have to". I used to hate playing guys that did this because I knew it was going to take many hours to break them down mentally. Then it would just come down to an "endurance contest."
There are players that have played pool for many years that never learned they can hit {approximately}90% of the shots hitting the inside "quadrant" of the cue ball. The only time you have to cue it anywhere else is when you need to curve the cue ball or change the angle coming off a rail (and "throwing a bank", in certain situations). 'The Game is the Teacher'