Sales taxes are hard to make progressive (they're usually regressive) and can be harder to enforce (if they're local).
It depends on your goals. It sort of makes sense that we have both, at differing rates.
The big issue I have with sales tax is that it is a much worse solution to the problem than a simple value-added tax (VAT). Most countries have figured out that VAT is more difficult to cheat.
Honestly seems like some mental gymnastics to me to argue that regressive is about what % of income is spent on taxes rather than amount of taxes paid but that's the argument.
(I know this isn’t true in practice because of exclusions from sales taxes, but we could imagine one that applied to all consumption.)
There is some strange axiomatic derivation happening in this thread. The term "regressive tax" has a specific meaning; we can just start with that as an axiom, rather than re-deriving all of economics. A regressive tax is simply one that takes a higher percentage of income from low-income taxpayers than high-income taxpayers.
It's a lot harder for a city to collect income tax than sales tax.