I strongly believe that battery percentage should not be in the world. It can be unsafe, your phone always goes flat and you always lose your charger cord.
Firstly, battery percentage should not be in the world because it is so annoying to people and unsafe. If you were getting chased by a bad and dangerous person and tried to ring someone and your phone was dead you would be unable to get help. Also, if you get lost you can't call anyone for help if your phone is dead.
Secondly, it hurts to see your battery on one percent. Because it takes ages to find your charger and if you have to go out you can’t because you don't have a charger.
Finally, you lose your charger a lot. It is sooo annoying when you don't have a charger and you have to waste your money on a new charger (2 mins later) you find your old charger.