Why live stream people talking about slides and static text instead of playing pre-recorded?

Seem like heavier load and risk of quality when you can stream a perfect recording instead (and then do the live Q&A stuff after and what needs real live user interaction LIVE)
Yes it's nice to practice live stuff even but maybe mostly many don't need that... just press play!
Also good for fallback as recording / multiple sources or silo somewhere.
For consistency JUST RECORD YOURSELF AND YOUR SLIDES LOL... then Jitsi chat after !

I'm sure I missed something
I labelled this post with idiot... please confirm that with a bit of reasoning... is it so far fetched?

Thanks overall,
#FOSDEM2022 #FOSDEM