Most snooker coaches teach some variation on vision centre, and stepping inward to the shot isn’t unique to sightright. However, one of the differences is that sightright is much more prescriptive...
But I think for some of the more sideways pool stances, it might be hard to form those from a square starting position while keeping the shotline in your vision centre the entire time.
If you watch:
Session 6 - The SightRight Stance
Stephen Feeney says:
In light of what Stephen Feeney said in that video, do you believe that SightRight prescribes that you should keep your vision center on the shot line the whole time during the step in? That was not my understanding.Remember, as you step into the shot to form your stance, keep your eyes on the Pocket SightRight. As you step in, the lines won't stay together, but when you are down on the shot, if you are sighting perfectly over the cue, you will see...[one of the various visual patterns that lets you know that your vision center is on the shot line].