PPF is definitely much thicker, and as others said it's around 6-8 mils compared to a 'cheap' vinyl wrap that's around 2-4 mils. There are thicker vinyl wraps and PPF's out there (and they cost more), but for the most part that's what you normally see. Also, the jobs of PPF and vinyl wraps are for completely different purposes.
Most vinyl wraps are just that, a wrap for your car to change the color. It does help protect the paint from UV and other elements (rain, bird droppings, etc), but it can still tear and take damage when it's hit with some force by something. PPF is specifically designed to help mitigate damage on your car's paint, and most PPF's out there might have a self-healing element where it can 'cure' itself from minor dings or scratches with some heat or when left out in the sun. Because of this, PPF usually costs quite a bit more for the same amount of area covered on the car. Also, being thicker makes it a more difficult to install compared to a more flexible & pliable vinyl wrap, so installers will charge more for labor.
Ceramic coating puts a thin protective coat over the clear, but it's not going to harden like people think and deflect rocks and prevent chips. One of the main purposes for a ceramic coating is its hydrophobic element of being able to bead water right off of it and helps reduce dust & dirt from sticking on the car. As a protection barrier, maybe for UV rays and rain water and possibly bird droppings (depending on the ceramic coating used and how many layers applied), but I wouldn't use ceramic coating only thinking it will protect my car from rock chips and freeway debris.
Different strokes for different folks. I'm not an installer, but I've worked in the auto industry for a few decades in the past and have done plenty of research and testing on my own.