It makes perfect sense to use Garmin WebUpdater for updating unit specific features. The unit is always keeping the "GarminDevice.xml" updated to reflect the current installed versions of files in the unit. This works well as long as nobody makes a home-cooked or edited firmware with mismatching FW & HW IDs for another region or GPS model. All of this is for units that uses USB "Mass Storage Mode" instead of the legacy Garmin protocol for serial based communication.

Garmin Mass Storage Mode Devices
Code:
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Other features that's depending on a map update is distributed inside the map update package. The map updater is also reading your specific units model code and applies the map update for that model. Voice recognition, 3D and JCV will only be distributed to the units who is capable of using those features.