I think this may be wonky. I get email notifications even though I haven't selected that option.
I have chosen "Notify", that I assumed would give me some kind of notification here at the site or a list of topics I've participated in. Since there's also an option "Notify with e-mail" just "Notify" shouldn't use email, right?
I agree it's unclear.
"No" notification seems to be the default, but the difference between "notify" and "notify with email" isn't specified. Like you, I'd have assumed that the "notify" option, since it doesn't mention email, wouldn't include email notifications.
Could be that the code underlying those options is not yet complete and/or stable, so we may need to wait a bit to see how things shake out.
Disregard.