Right, but if a tipped employee in a lower-tipped-minimum state doesn't make the full minimum wage when their tips are included, it's a lot easier in a place like that for a shady employer to fail to top up their wage. Yes, in theory there are ways for employees to get this enforced, but in practice they are very reasonably and understandably wary about making use of those legal avenues.

Not to mention that in a state where there is no lower tipped-wage minimum, all tips go to the employees directly. In a state where the tipped minimum is lower, tips effectively go to the employer for the amount between the tipped minimum and regular minimum, as that's a cost the employer would otherwise have to pay.