> Mmm, that means we'll get a lot of logs even when everything is fine, doesn't it?

Not really, as users almost never change their email addresses.

> Can't we generate an event or so?

Sure, logging is just the minimal way to make email changes traceable, which can be used to track abuse. An event, yeah, but in the end we have to store it somewhere, and this is either file system (logs) or database, and using a database model for that was a bit overkill in my opinion. We could do this once we allow the assignment of multiple email addresses to user accounts (similar to OpenID), but I'd skip that for now.