Working from your email inbox is pretty efficient with Phabricator, but there is a mild inconvenience with transaction emails that reference other objects.
Usually if you mention an object in a comment (like Dxxx) Phabricator will turn this into a link to the referenced object in an email. However, sometimes you'll receive an email containing something like:
user added a revision: Dxxx: Title of the revision.
Unfortunately it's not possible to quickly click through to the revision in this case. You'll have to open the task (on a side note, the link to the task is often hidden by email clients because it's repeated over several emails), scroll down to find the revision and click the link.
I think it would make the email UI a little more consistent if all objects referenced in emails would link to the object.