Why?
No specific reason for this but:

*You may want to watch your battery level going down in minutes with your own eyes.

*You may not want to charge your battery before it completely goes down though this has no good!

*You may want your friends to concentrate on you instead of their phones.

*You may challenge your friends to see whose battery is the best!

*Or you may just want to do it for nothing at all.

I hope you enjoy!!