As you already figured out, your PPO HSA plan option is less expensive overall in every situation. The premium + out-of-pocket maximum (worst case cost) is less than the premium alone (best case cost) of the other plan, even before the tax savings of the HSA. Clearly, the PPO HSA plan is the best choice.
Why would anyone want to choose the other plan? With the PPO plan, you hit your deductible the first time you go to the doctor, and the insurance starts paying expenses right away. This means that you won't be getting large medical bills when you go to the doctor. With the HSA plan, you have to pay big medical bills. Some people are bad at managing their money and budgeting, and would rather have this money taken out of their paycheck than to risk spending it on something else and not have enough to pay their bills.
Just to be clear, your best bet is definitely the HSA plan. Just make sure that you take some of the money that you are saving in premiums and put it in the HSA, so that you have enough to pay those large medical bills.