Yes, I am really sure.
I am even more sure that something changed two days ago, that caused me to suddenly receive a big flood of emails, without me having changed any setting whatsoever. This is a fact.
I turned off all my email preferences and still the emails continued. Only removing the pages from my watchlist stopped them.
So apparently it is now no longer possible to watch discussion pages on the site without being flooded by emails. I would like to have that functionality restored.