You made a logical leap there. I don't know about the engineers opinions but its mostly just ironic and funny. This is not just cherry picked examples, you can see in the comments the bot starting conversations with this kind of stuff.
Did you read the blog post? This is only one example from the first part of it. You can find more useful examples if you read a bit more.
For example, if you write "Pseudo Code:" after a chunk of code, the copilot will explain the code for you.
It does! I didn't test it on huge functions yet but technically speaking, Codex is able to take into account about 14kb of memory, which translate to a few hundreds lines of code :)