You will find it a great help to estimate the battery life by learning the power consumption of the system with this module. In the solar powered projects, it helps to record the status of the battery power change in a day or even months, which benefits to understand the power balance of charge and discharge of the solar system.
Gravity: 3.7V Li Battery Fuel Gauge Connection Diagram (Arduino UNO)
Gravity: 3.7V Li Battery Fuel Gauge Connection Diagram (Raspberry Pi 3B)