Why people order Nav?

Yesterday I played with the built-in Nav at the dealer and with Garmin in Car Toys. Here are my thoughts:

BMW Nav:
- is not easy to use. Typing an address is a nightmare without remote or touch-screen
- it does not allow to find a place/address by entering a phone number
- it disables the ability to play MP3's in E90
- it replaces the "BMW professional" radio/CD player (which I think is very good) with very basic CD/DVD slots
- it forces to control the music system through single iDrive knob (instead of multiple functional buttons on the "BMW professional" radio/CD)
- from what I read (I haven't tested that) the directions are not as accurate as with third party Nav systems
- it is extremely overpriced at $2000
+ it looks very nice on the dashboard as a built-in system (some people disagree and claim that one hump looks better, so I think it's an individual preference)
+ it has large screen

Garmin Nav:
+ is very easy to use, has lots of functions and touch-screen
+ it allows you to enter a phone number to find associated place/address
+ doesn't disable the ability of playing MP3
+ leaves the original "BMW professional" radio/CD and climate control in place
+ is portable, so you can take it anywhere
+ costs anywhere from 500-1100 depending on model
- doesn't look as great as built-in Nav in the dashboard
- has smaller screen

Basically, taking functionality and price as priority, Garmin by far wins in both categories. So, why do people buy BMW Nav then?