App modules are great to customize User Experience for specific business needs by tailoring what users see (sitemap, dashboards, forms, views, graphs...).

Today they can only be associated with Security Roles to allow access to them.

However, most users connect to Dynamics 365 either through the base URL (domain.crm.dynamics.com) or through the Office 365 app switcher. So if they don't purposely go the App in the menu, they miss the App that has been tailored for them and use the "main" CRM instead.

It would be ideal to avoid these situations and make the user directly access the App that has been associated as the "Default one" for his or her security role(s) (with some sort of "role priority order").

That way, when a Sales user connects to domain.crm.dynamics.com, he/she would be automatically redirected to his/her default App and have a unified and consistant experience across the application