Funny anecdote: I wrote a GM script a loong time ago to block the FB ads. And promptly forgot about it.
So I was a bit confused when people would mention FB ads, and I was like: where are you people seeing these ads? This confusion reigned for a long time until recently, when one day I opened up my GM userscript manager panel and saw the FB ad blocker. Oops! So, for me, ads are not an issue (so far).