OK you are beginning to think in
permaculture design. Does this demonstration have application to my design? You ask this under the topic of mulch so that is how I will direct
the answer.
What was the purpose of the demonstration? to
sell tools. He also sells rakes. Besides killing the weeds what was his objective? Most likely with his cultural practices to make a dust mulch.
The purpose of a dust mulch is to produce a dry loose layer that stops wicking of moisture to the surface and is hostile to seed germination. Disadvantages is it depletes soil life and nutrients
and is only effective until the next rain or watering. As you mentioned leaving the hoed weeds on the surface when they have seed heads as in the video continues to
feed the weed seed bank.
Use the shuffle hoe more frequently and more shallowly then is advantageous for minimizing soil disturbance and making a cop and drop mulch.
Leaving them may offer some soil protection but cutting them and leaving the
roots and soil undisturbed may give better protection.
Bottom line: do not feel that you
should do everything the other person does because your circumstances and goals my be different.
Do not let other peoples standards make you feel like an inferior gardener because your garden does not look like theirs.