Because those battery stats which are stored in the batterystats.bin file, are only used to maintain information about what is using the battery when not recharging. That is, it essentially holds the information displayed in the Settings > Battery screen. Nothing more, nothing less. Thus : It has no impact on the current battery level shown to you, and it has no impact on your battery life.
What’s more, you’ve probably noticed that the battery usage data is reset once you recharge your device anyway. From this you can correctly deduce that the battery stats are wiped as well ; every time your device is recharged.
Best regards