Does exactly like it says Rated 5 out of 5 stars

Good, but on Android 4 and higher you can close Firefox with the app switcher.

This review is for a previous version of the add-on (1.04). 

This is true ! And was discussed internally quite a bit before deciding on the change. (They knew there'd be people like me :P ) I like the exit-from-app method as it feels cleaner to me than switching to the OS.