Oh yeah there's that too and now I also get them in other languages than English but they are just Google translate version of SO.

I recently noticed that a number of SO questions have even been turned into Youtube videos containing a slide-show of the answers, now :-(

I absolutely hate this. Scanning a video is so much more difficult than just scanning a written explanation. If these videos are being monetized, I think that's a problem. If they are, someone could just create a channel by converting SO questions into videos.

The question I have is what kind of keywords are people using on these videos that Google feel is more worthwhile than the actual text of a written version of the content? Or is the algo so heavily weighted to pick a youtube link?

Having worked a stint in social media for 4 years there was this huge guideline from Facebook to push publishers to churn out videos. I suppose Google ranking algorithm favors Youtube but i don't get Google's reasoning behind that. Engagement because of embedded ads ?