This approach of ignoring the rest of the world and explaining Swift concepts as if they exist in a vacuum is frustrating and counter-productive.
Even if this were a totally new feature, I'd expect links to research papers.
It is one thing to present end users with 'shiny new iphone' every year. It is another to treat developers like idiots and have every swift related announcement be this sales pitch of 'great new feature' when in reality they are all features other languages have had for decades (and are thus mature, while Swift is always half-baked and full of gotchas) and this is yet another re-implementation of what already exists with undocumented arbitrary differences that people then have to spend time to figure out (aka free beta test) when I'm sure the people who implement this stuff (hopefully) know full well what trade-offs they are making.