But you said that you get the "benefit" of lower prices - but I just don't see that benefit if it's mandatory to then tip 15%. Whatever reduction in price you're getting you'll pay in tips, so as a customer you're getting shafted either way. No?

You're not getting shafted. If you tip, you're paying the same amount as if there weren't tips and the prices were raised to account for it. There's nothing "shafted" about "paying the same amount".

The only differences are - You can choose to pay less if things aren't good, or pay more if things are great. - If you're someone that is heavily impacted by other people's opinions, then you may feel bad tipping less. But all that means is that you don't get one of the benefits.

You get the "benefit" of lower prices... and you're expected to tip to balance the scales.