Oh wait. Sorry, if you are watching a topic that means you get emailed for all new replies to that topic.
So it’s immune to that setting, considering it only “blocks”:
replies to you
quoting you
@name mentions
invites
A new reply to a topic you are watching is valid, since it is (probably) not a reply directly to you, but you said hey I am so mega interested in this topic, why don’t you go ahead and notify me about every single reply to it?
If you are watching a category, you’d also have the same phenomenon for every new topic in that category. You previously said hey I am so mega interested in this category, why don’t you go ahead and notify me about every new topic created in it?
(Which reminds me, we probably need an additional category level setting for “notify people just about the new topics, but not any replies”. It’s been requested.)