From the same link, being able to take a full page screenshot (as in, below the fold) is also very excellent. I notice from the YouTube page description there is a further shortcut:
1. Open the Command Menu with Command+Shift+P (Mac) or Control+Shift+P (Windows, Linux, Chrome OS).
2. Start typing "Screenshots" and select "Capture full size screenshots".
I needed this literally yesterday, when I used MS Paint to cut and paste a screen together like a total mug.
Great! I was having trouble taking full size screenshots using UI last time I tried (apart from adding a custom device for desktop). This time I found "Laptop with HiDPI screen" as well which I believe was not there earlier.
I was stoked when I found out about it. Sadly, the fullsize screenshot makes my stylesheet switch into portrait mode and then I get the mobile look with the bottom half of the page completely missing.