An SSB is an application with an embedded browser designed to work exclusively with a single web application. It doesn’t have the menus, toolbars and accoutrements of a normal web browser.
At the very least, you can't rely on the chrome for alerting the user to phishing etc.
I installed Prism, and for each SSB application you create, you specify what UI components (e.g. location, status) will be displayed.
Separately, might 'designing to work exclusively with a single web application' interfere with SSO (e.g. redirects)? Presumably not, if the SSB just uses the underlying installed browser.