Earlier quoted context omitted.
Yes. It is exactly that.
Hmm. Maybe I should try uBlock. I usually don't like adblockers -- both on principle, because I believe in paying for what I consume, and because they tend to subtly break a website and cause hours of headaches at least once a year -- but I don't like feeding the beast either. I'll look into this.
Your former comment indicates that you care about page load times, in which case an adblocker will typically reduce both UI yank and certainly network usage, in case you’re constrained.