Canvas submission notification emails for instructors currently contain a link titled "Click here to view the submission" that links to the Submission details page for the submission. It would make more sense to launch this link in SpeedGrader.
As is, the Submission Details page doesn't even have a link to SpeedGrader. On top of that, the only hint text on the page (when hovering above the View Feedback button) is geared for students. Please see the screenshot below for more. Thanks for your consideration!