> personally do not understand how it can be convenient

It can be very convenient for retailers since sales can vary in different counties let alone states:

https://en.wikipedia.org/wiki/Sales_taxes_in_the_United_Stat...

just try to imagine what a mess it would be if any advertisement, price sticker etc. would have to show the full price.

It wouldn't be difficult at all. Price stickers are printed/managed in store often enough. Any company that allows you to purchase online already had to deal with differing sales tax, and everything is owned by like one company right now anyway so they already have systems in place to deal with differing tax rules in different states.

But it's not just states. In California (and I guess many other places) towns in the same country can have different tax rates. Sure price stickers is not an unsolvable issue but advertising prices including tax publicaclly would be almost impossible.

> everything is owned by like one company right now anyway so they already have systems in place to deal with differing tax rules in different states.

Yeah I agree it would generally be a much higher burden for small businesses than for Amazon.

Why is calculating the price with correct tax possible but not the advertising of that price? What is the physical bottleneck?

GP has it wrong. It's entirely physically possible to advertise prices including tax, but it's illegal to do so.

I see it as a mess in the tax system being projected to customers. I do not understand the choice of taxpayers to have such system.

Well local jurisdictions are funded by sales taxes they themselves set. You live in a tourist town? Well higher sales tax results in more funding for local services and possibly lower property taxes and you could just drive to the next town if you want to save the 1-2%. What's not to like?

There’s so much wrong with this, that I don’t know where to start. So let’s start with the elephant in the room: driving to next town to buy something that is available locally is generally a red flag of market economy failure, because it is incredibly inefficient and environmentally harmful.

Then there’s an incentive to produce higher inequality: high sales tax affects mostly poor, while low property tax usually benefits rich. Poor people are usually underrepresented in democratic institutions, so it would not be surprising if inverse redistribution would be a frequent problem.

Finally, local tax as a way to fund communities is not the only alternative and relying on it would mean that some communities will never get out of financial trouble. Tourist towns are minority, after all. Other countries just keep some of the collected VAT locally and redistribute excesses from richer to poorer communities through federal transfers (German solidarity tax did exactly that, for example).