As far as I know, if you pay only for true power, and not for reactive power, consumed by your appliances, then this capacitor would save up no money to you.
Moreover, the value of the capacitor is different for different loads.
The more inductive the load, the larger capacitor you'll need to connect.
Most people could care less about the electricity they use. 80% of the population cant tell you the difference between an amp and a volt. Power factor is way over their heads.
If you want happy customers dont make them think. Thinking hurts most people.
And customers that think will find problems with your quality of service and demand more for less.