Earlier quoted context omitted.
I think separately listing taxes has the benefit of transparency - you know how much the government is taking and can make more informed electoral decisions.
With a single Federal Goods and Services Tax (GST) as in Australia, you know it is 10%. All prices include the GST and are the price you will pay. There are no other sales taxes . Everyone knows what the government's cut is. Everyone knows how much they are actually paying. I can't see why anyone would want a more complicated system. Clarification: Many "essential" goods like simple foods are GST exempt. They will be…
In Canada, the provincial sales tax differs in each province. The federal rate is 5%. Alberta has no sales tax, whereas Ontario charges 8% (post-harmonization it's a HST of 13%).
In the US, the sales tax differs not only by state, but by county and city.
The tax situation in Chicago is particularly bizarre.
The sales tax in Cook County, where the city of Chicago located, is 10.25%. The sales tax one county over (say Dupage County, 15-20 miles outside the city and still part of the greater Chicago metropolitan area) is 8%.
Restaurants in the City of Chicago (but not other parts of Cook County) charge 10.75% because there's a city-specific restaurant tax.
The different tax rates create strange arbitrage opportunities. If I buy an iPhone from an Apple Store a few miles outside Chicago, I get an automatic 2.25% discount.