You're wrong. There are two ways you place your hand on the table (only two). You can drop your hand down to the cloth or you can slide your hand into position. Dropping your hand is random for the most part while sliding your hand into final position allows the players to align the hand more accurately. I believe it was Tom Simpson who refers to this as a helicopter landing versus an airplane landing.
The slide has the LEAST variation between the two.
I have to agree with this. Sliding into position is a lot more accurate than placing the hand into position for the main reason is that the sliding motion "coerces" the mind into making the minor adjustments as part of the motion -- one fell swoop -- and keeping the structural integrity of the bride intact when it comes to its final position. On the other hand, minor adjustments to placing the hand on the table have to be made *after* the hand is placed on the table, and this teases the mind into doing things like slightly contorting or twisting the bridge that minor amount (thereby possibly compromising the stability of the bridge), instead of the proper motion of picking the bridge hand up and replacing it into the correct position. (In other words, you can read "laziness" here -- we're all guilty of taking shortcuts when we can. But in placing the bridge hand on the table vs. sliding it into position, the shortcuts taken can have a more profound effect on accuracy.)
I do a different method of sliding my bridge hand into position. I don't use pivot-based aiming systems, so my method of sliding the hand into position is to slide it FORWARD, into the line of the shot, rather than from the side. This does two things for me:
1. It helps cement into my mind the line of the shot (the cue ball path to the object ball). That is, not only does my stance completely conform to the line of the shot (i.e. the snooker stance), but my motions into the shot do as well -- stepping into the shot, and sliding FORWARD into it. It really is "committing" to the line of the shot.
2. Sliding the bridge hand forward helps to "taughten" (if that's a word?) the skin of my bridge hand where it touches the table. I.e. the heel of my hand and the fingertip pads of my middle/ring/pinkie where they touch the table. By sliding those contact points forward, it pulls the skin back until there's no more slack, and enhances stability during the somewhat violent forward motion of cue delivery -- especially if, during the heat of battle (i.e. I'm under a bit of duress during a match in a tourney or whatever) where my hands are sweating a bit and there's a bit of drag in the bridge hand. Keeping the skin of those table-contact points taught really helps.
Hope this is helpful,
-Sean