Please enable Smartsheet’s approved domain and add SharePoint to embed content for WorkApps.
I second this, I was very disappointed to attempt and learn that it was not achievable. Based on a segment at the Smartsheet Engage conference, one of the best ways to implement Smartsheet is to allow our users to use the tool without knowing they are in a separate system. This makes it a challenge to publish something such as a Word Document (published in SharePoint) or even a SharePoint site. I am using WorkApps for a project plan and I need full integration of the tools.