Initially, I thought this add-on was great. Exactly what was needed for a slow internet connection. BUT... it then added links in the context menu inviting me to take a "free virus scan" or to try a "free on-line translation service"
I notice that the screen-shot now includes these advertisements, so it is not a "deceptive practice", however there are other, (arguably more versatile,) add-ons that do the same thing and much more, (such as additionally block Java and Java Script) with convenient tool bar buttons that indicate current status.
So if you feel you need this functionality, my advice is to keep looking