Yeah, it also gives you a feeling for his speech pattern. If you use your dvd remote to skip from scene to scene really fast, you end up hearing the same repitions in his speech over and over and over again in rapid succession.
"Um"...click..."Ok"....click..."Alright"....click...~nervous laughter~...click..."Um"...click..."Alright"...click...and on and on. His commentaries are awesome, because he makes the commentary track alone worth the purchase, and thats no small feat. I mean, he literally talks through the whole thing and turns the commentary feature, not into a supplement to the movie, but rather into its own interview/experience.
A Tarantino commentary is pretty much the complete opposite of say...the Mel Gibson commentary for Braveheart.