I mean that’s mainly it… it’s amazing at clearing adds off of news articles general viewing pages like blogs etc… but yes as you said, it’s not particularly great for things like youtube/spotify etc… things that deliver the ads through the same source as the main content.
It’s possible to assume that the professor did the math.
But yeah any time machine would also basically have to have space travel built in to compensate.
They knew that when they wrote Dr Who (IE the time travel machine is called a TARDIS (Time and Relative Dimension in Space).