It is a difference in who decides how much they’re paid. In a traditional business their pay is at the discretion of the business and thus in competition with what could be the business’s profits. Tips are inaccessible to the business, so they get paid more closely to what consumers are ok with paying. I’m probably paying more too because of being guilted into feeling like I must tip x% because I’m directly responsible for the person’s wages.

These two points mean there’s no guarantee a tipped wage would convert 1:1 into an hourly wage if we simply removed tipping, even if the value provided by the tipped employee stays constant.