Root is definitely the backbone of a ton of work done in experimental particle physics but it is also the nightmare of new graduate students. It's affectively engrained into particle physics and I don't expect that to change anytime soon
I've actually done some volunteer work at the James Clerk Maxwell house. The people who run it are great and love to show people around if you want an in-person tour. Just email and they can organise a time.
I was thinking the same as you. It seems to be another term for code folding. It is where you collapse parts of a source file into a single line so you can just focus on the part of the source file that you are interested in.
I don't think you need to be hard on yourself. Creating content up to the standard of 3b1b requires skills that can be far removed from what you want to teach.
Having knowledge of a topic is one thing but being able to create entertaining and educational content around it is another.
This requirement just does not make sense to me. Why would Microsoft even have this requirement? Do they want to force users into an account so it is easier to lead them into Office packages? It can't be for greater data profiles on users since they could do this in other less explicit ways. Microsoft just doesn't have the ecosystem like Apple to make this worthwhile from their point of view or the users.