Claying and Glaze Question

[SATracker]

I was watching a Chemical Guys link that was posted on FB and the guy giving the presentation made a couple of interesting comments.
1) The claying removes the contaminants from the scratches of the paint (6:26-6:36 in the video) and
2) After claying the paint a glaze should be applied to fill in the scratches (8:50-9:07 in the video) and after a glaze is applied, a sealant and wax is then applied.
I thought the claying process shaved off the top of any contaminants (only Iron-X removed iron contaminants) and I'm curious how many of you add a glaze to fill in deeper scratches before sealant & wax.
https://www.youtube.com/watch?v=MNYACHcDEaI#t=14

[af90]

I'd rather just polish and get rid of the scratches.

Now if you're just trying to do something quick and in a pinch or say getting ready to sell a car upcoming then a glaze can definitely have its merits.

CG Blacklight is a pretty good glaze overall.