Technically the thing in the video isn't a walkthrough as much as it is a demo, but in either case they didn't use it as a substitute for proper affordance in the final product design.

Like a matryoshka doll, it's best to educate your user at every level of interaction, whether explicitly (FAQs, copy, instructions, walkthroughs, etc.) or implicitly (affordance, appropriate skeuomorphism, etc.).

Apple is generally good at both. For example, when you ask for help, an app will both show and tell. Most apps are just "tell," instructing you where to go and what to click.

Apple: http://cl.ly/image/0f161f1f1L1s Google: http://support.google.com/mail/bin/answer.py?hl=en&answe...

Oh, what, sorry? The GMail filter UI doesn't look like that any more? http://cl.ly/image/2x1A2J1Y0U1a

Too bad!

None of tbe apps featured in that commercial have walkthroughs.