A government continues generation after generation, carrying with it the hopes and dreams of citizens for a good life for themselves and their descendents. Good governments are designed to create and maintain institutions that serve order and stability. Good governments strain to impede the mad and irrational acts of individuals, while allowing creative and positive impulses to move forward unchecked.
Taxes serve two purposes.
They create revenue, and they are a method of social control. Tax credits for charitable donations encourage donations, the social benefit outweighing the decrease in revenue. Those jurisdictions around the globe that wish to become economic powerhouses will eliminate sales taxes altogether. In order to salvage any revenues from Internet commerce, some kind of uniform international tax may be necessary. But in whatever form, uniform taxes defeat the social control function of taxation.