What does a firmware password protect? If I create a firmware password on my MacBook, what does that protect me from?

Does it protect from any of these:


Reformatting the hard drive.
Switching OS to boot from (e.g. if Boot Camp is installed).
Restoring the laptop to its original factory settings (i.e. reinstalling OS X).
Installing another boot loader such as rEFIt which bypasses the firmware password
Installing a firmware password will prevent anyone without the password from selecting a different boot disk to start up the computer. It will also disable some startup key sequences, like getting into single-user mode. I don't know how the firmware password interacts with something like rEFIt.

However, if someone can open your computer, they can disable the firmware password by pulling one of the sticks of RAM and/or just access your hard drive directly and do what they want with it.