What actions are performed by Install OS X Mountain Lion.app that are not performed by InstallESD.dmg without the app? Recommended

Apple provides and recommends use of Install OS X Mountain Lion.app


that is, "the app" – in its entirety. 


For Build 12A269 for OS X 10.8, the version of the app is 1.3.12 (351).

Known

Ignoring parts of the app – with InstallESD.dmg alone:


installation may succeed.


(The same is true for Lion when parts of Install Mac OS X Lion.app are not used for installation.)

Unknown for Mountain Lion

The full list of: 


things that do not occur, things that may not succeed, when installation is attempted or performed with something other than the app. 


My initial plan is to accept an answer that provides either: 


the fullest list; or 
the best set of evidence for a partial list. 


Starting points

com.apple.Boot.plist(5) OS X Manual Page – page dated March 17, 2011 for 10.7.4, the same date appears on the page within 10.8. 

For Mountain Lion on some types of hardware, there may be a unique distribution (ESD). 

Food for thought, just part of the Lion experience: June 2012 discussion of Downloading Hardware Specific Lion Installers (cache)(copy).
My working theory is that there are no meaningful differences in actions performed under the app as opposed to the DMG.

One could argue at a low level that the difference is that invoking the Install OS X Mountain Lion.app bundle loads app and UI frameworks that simply mounting a DMG does not, but that's not exactly the intent of your question I'm sure.

Any meaningful installer-level actions should be identical in either medium, since the majority of the resources are in the DMG, and the DMG is in the app. The app must mount the disk image in order to get at the necessary assets.