Protecting the tops of deck joists - or not?
There’s always “Good”, “Better” and “Best” in any construction project. I’ve never seen the tops of pressure treated deck supports protected with “peel and stick” membrane, and I live in a very wet area of the U.S. (We get about 60 - 80 inches of rain each year.)

All of the ideas he recommended in the video you referenced are great, but membrane on the top of the joists seems extreme. In fact, there is a greater chance that rot will occur at the ends of each support, (because water “wicks” into a board far more in end grain than in side grain,) than on the tops of the supports...which he doesn’t mention. 

BTW, there is nothing in the Code that requires a membrane on top of deck supports.