The Magic of Passport Cover

I'm sure many of you also same like me thinking what the use of the rubber band at the passport cover there use for?
FYI it's not just simple only for tight up the passport only...
It's has a special way to use for!!! Not just only to hold your passport to falling out from the cover but also can use as a bookmark too. Once you open the passport it will automatic like got magic one open the page where the rubber band are!!!
Please enjoy my video~~