I'm firmly convinced that it's bad for us.
As is watching a dozen vids in one session and switching back and forth between them. It's possibly the most mentally damaging way of doing the whole thing. It's like TikTok. Imagine doing that with movies.
Might do an IRL sexual partner who enjoys foreplay a favour though. I dont know that reprogramming our brains to only react to hardcore scenes is doing ourselves a favour either.