The “semi-public” mail e-mail address you use to sign-up in Bugzilla will eventually get spam. Here is why…
Bugzilla has a problem
Because the mail address shown when logged in there is always a way to scrape mail addresses and use these to spam people. Fortunately, they are hidden when one is not logged in, at least.
Anyway, that is not enough. Because I use a mail forwarding service (similar to what Firefox Relay does) and thus I can see my mail was apparently retrieved from Bugzilla (it’s unique and only used there) and used to send me spam today:
I then blocked the old mail and changed my mail to create a new one. However, not everyone has that luxury and thus mails may end up in spam databases inevitably. (And even for me, it’s quite annoying.)
IMHO, this is not acceptable.
A Setting allowing to hide the mail? AFAIK there is no need to display it in the first place, so IMHO you could also just switch everyone to usernames and then hide it.