What is the thesis of his talk? Is it worth viewing?

He tracks down where the statement "Premature optimization is the root of all evil" actually comes from, and whether the assumptions set out in the text where it was published still hold.

It doesn't really contain anything new or earthshattering, but if you find diving into the history of programming as a discipline interesting, it might be for you.

I would recommend it to anyone who liked the rambling style of "The big OOPs", but imo that one was better. I still liked it.