(+ for the presentation style with the "devil's advocate" approach and the different roles played by the presenters.)
Adaptive Cards are a new way for developers to exchange card content in a common and consistent way.
“Cards” are used to display your content inside a host experience, they came from social media. The content they contain could be Articles, Reservations, Weather, Reminders, Videos, Boarding passes, Restaurants, Receipts.
A boarding pass fits as an adaptive card.
A demo with a scuba travel booking using an adaptive card on a webpage, and confirming the booking inside Microsoft Teams, or Outlook. The cards can also been seen in the windows timeline. Using the bot framework, the booking can also be done by talking to Cortana who will show the cards as well, there is a "speak" tag in adaptive cards.
For developers of adaptive cards there a lot of documentation and cards to be used as inspiration at http://adaptivecards.io (It is almost as a developer studio where cards can be built and tested in various platforms.) An adaptive cards designer will also be released on this page.