To be fair, if I were building the system from ground-up, I absolutely wouldn't make tipping at restaurants a thing
So if your argument is
"Hey, there's this horrible social convention that basically involves you paying extra to keep restaurants from paying their servers a full wage, and is inefficient, widely disliked, and generally considered to be growing out of control. It's admittedly a bad system, but it's built into expectations now and has become a social requirement. Anyway, I was thinking we should introduce that in MORE areas of daily life"
That is ...not a strong argument for NIL (as currently practiced)