Nice !
I've watched the whole thing and have these comments:
You say (6'25") that question-level "mini-banks" is a new feature in Moodle 5.
That is not (exactly) true; such containers have always existed, only the difference now is that they cannot be named "share-able" in Moodle 5's terms. I recognize, though, that the way you present it like this makes the whole story simpler ;) .
7'50" - Probably worth advising that after a course is duplicated, the quizzes in there could be renamed slightly (by the teacher), so the quiz names don't repeat in the question instances report. An improvement suggestion to the devs could be for the question instances reports to also list course names (eg. short course names) & links to them?
8'18" - the fact that changing the question in a later / duplicated course / quiz does not change the earlier question instance can be an ASSET. I would not want to auto-update courses that already took place and are closed. (Of course, with question history enabled, and specific versions rather than always "latest" versions of questions used in a quiz, we can "protect" older, "archived" courses also if (shared) (course-level) question banks are used).
I like how you conclude that "Kathy is happy" and that she can continue improving the course over time 
Great idea of the "honesty question" ;)
10:48 - yes, that duplicated name of the question bank after course duplication IS confusing. I think maybe "(copy)" should be added to the back of the original question bank's name in a course copy ? (BTW: what's not yet stated yet is that question banks can be "default" for a course, but one can also add more than one...)
11:48 - BY the way : Quizzes without questions in them could - in the course editing mode - bear some warning flags, I think. Another improvement suggestion for the developers perhaps...
12:40 - Maybe I would add here that such decisions need to be taken carefully; after you move questions from quizzes to course-level question banks, there's no easy way back.
14:03 - caveat - the author if the imported question is now Kathy , NOT the original teacher. Creation date is the date of the import.. Maybe a point worth mentioning with your final notes , like the one about copyright?
Overall, you mention question versioning a little, perhaps sufficiently. For me, though, this is a feature I have yet to learn how to explain to my users best, and how to control it if needed. Your caveat note at 17:00 is good; but when you once refer to that question version here - 14:35 - I thought : hmm, why alert the viewer about this fact specifically here, all of a sudden? What's the significance ? So, maybe in the next version of the video you could treat the question versioning aspect more systematically along the way? Hmm.
GREAT STUFF !!!
I only hope some of my comments make sense.
Cheers and THANKS !
Przemek