What is the point of electric cars if they still use the electricity produced by electric station (which in turn use earth resources)?

There are two major aspects:

1. The energy used in the power system is derived from various fuel sources, that include renewable energy sources such as solar and wind, so this means that there is less carbon emissions;
2. The carbon-based fuels that are utilized to generate power at large-scale power stations can be converted into useful energy with greater efficiency and at a lower cost than small internal combustion engines using diesel and gasoline.