I really hope that Multi-Account Container Tabs feature is in the todo list of Edge team.
As you know, Firefox is the first major browser to introduce this innovative functionality for safe and organized browsing experience. But Multi-Account Containers can also be used by web developers as an important and time saving tool. This can be one of the big differentiating features of Edge.
While building multi-role web applications we need to constantly logout and login with different user accounts. There should be a better way to improve this workflow.
Incognito mode: Gives only one extra session.
Multiple profiles: Different profiles are separate instances. Currently it is not possible to sync among multiple profiles. So even profiles allow multiple sessions, it is very difficult to use as a workaround for multi-container tabs. Specially without history, bookmarks, and passwords the benefit of multiple session is very little.
Multi-Account Container tabs
Allow syncing among multiple local Edge profiles. Because it is not possible to create so many real online Outlook accounts to get container tabs like benefit.
To make it even helpful allow automatically merging data of selected local profiles to one chosen Outlook profile.
Show option to re-create those local profiles when logs into Edge in another machine with that consolidated Outlook profile.