Here's the answer from our desk:
If they have the Edit/Run permission under "Performance Analysis" and "Performance Analysis > Discover" they will be able to see the Discover icon in SIMS and access the Discover configuration tool.
In addition, they will require certain permissions to be able to view/access certain graphs and data in Discover, i.e. the data they can see when logged into SIMS .net under the Student-Teacher view (e.g. student, assessment, attendance information etc...) they will be able to see in Discover.
If they do not have permissions in SIMS and cannot see the icon in SIMS, then they can still access Discover (from the start menu or shortcut), but cannot view the data/graphs.