The reason electric companies want you to save electricity is that when you use less electricity it costs them less to produce and so they actually make more money when you use less electricity.
It would seem that the more electricity you use the more money they would make which is true but when the electric grid gets overloaded by everyone using lots of electricity then it requires more generators to be running.
In some cases it may even require that the electric company start building additional power plants which are costly and hard to get built.
It takes years to get permits and planning permission to get a power plant built and in operation.
So if they don't need to build another power plant then that helps them.
I used to wonder that myself as why the electric company wanted me to save electricity and save money and that is what I found out.