It's all about feel
One in a bazillion can play with any success without pre-lim strokes. You may as well take a running start on every shot. You could enter the Olympics in the Javelin Event.
When standing over the shot its best to feel the stroke while analyzing.
When you drop in you are at a different view point, its best to fine tune the aim, feel the stroke, the weight of the cue, no matter how you do it, it is yours and yours only, your style, your feel.
It's about the feel, the flow, the rhythm and timing. It all aids in a smooth delivery
One stroke, or no stroke, is good for one thing, when teaching or learning how to fall into the proper stance and alignment.