Corps. All of the bells and whistles it has ties into the corps tenant which includes isolation of things like sync’d profiles, seamless sso, favorites, extensions, etc

Since it’s all under the tenant, all of that data is subject to the same privacy and policies the corp and MS agreed to, which makes it easy to work with other companies that have their own client policy requirements.

MS also makes it easy to control and harden all of their products including Edge using policy controls from a single UI.

You can’t do any of this with Firefox without extra effort.