Re: Makes sense
The US doesn't have a sales tax. That's assessed at the state level and depends on the state. Oregon, for example, doesn't have a sales tax (Oregon's more of a "settle down" state, so they get you with the income tax and other fees instead), while New York and Florida have historically high sales taxes (due to high levels of tourism and/or visiting traffic--you can nail out-of-staters with a sales tax).
Besides, one key difference between sales tax and VAT is the point of application. VAT is applied at the wholesaler level (it's the retailer and any middlemen that are charged the tax--they just pass the cost down). Sales taxes are applied at the retail level (the customer gets hits for the tax and the retailer has to report and pay that tax to the government). I've noted that one advantage to a VAT is that it encourages honesty since anyone trying to evade the tax is likely to get reported by the next higher link (lest they get caught up in it).
PS. As of present, states lack the authority to force a business to charge a sales tax for its residents unless the business has a brick-and-mortar presence in that state, as that runs into the Commerce Clause, meaning they can't do it without authorization at the federal level. Congress has yet to pass an act providing such authorization, and they're pressured by e-tailers like Amazon to not pass one. Some states like New York can pressure some firms like Amazon by targeting affiliations established within the state, but not every state can use that angle.