Economists will always say that the tax should be explicit, and it should be placed for the people that ultimately pay for it. But pro-taxes people, mainly the government, want higher revenues first, which means putting a tax wherever you can, and that is about what is politically feasible, not about what is economically sound.
The end result is a hybrid of both interests. For example, San Francisco charges sales taxes, known to be regressive and punishing to poor people, but at least you know you are paying them on a ticket. Other countries, like europe, hide the VAT taxes, so it looks like you are not paying taxes at all. VAT reaches 10~20%, sales taxes in SF is around 6%.
Making it explicity DEFINITELY reduces it.