It makes the taxes visible and painful and they will therefore (potentially) not rise as fast or as much.
But yes, that’s exactly why the American right makes taxation so cumbersome and horrible: to make people think that taxes are bad, as there’s this assumption you can have civilization without paying for it.
Need to balance transparency in pricing vs. visibility of taxes. I don't think sales taxes are actually all that visible most of the time- it's not like the cashier is telling you "and your taxes are $X." But it does make it much harder to detect if the store is charging you more than list price.