Daniel, I'm inclined to agree with you. I've been working on cars a lot of years and have never seen a catch can on anything but kids' imports. Hell, I thought they came free with their fart-can mufflers.
I'm not questioning whether they work or not.
Do they catch oil? Obviously.
Will they save your engine from certain destruction? Highly unlikely.
If they did, manufacturers would be installing them from the factory and you'd be paying for a billet cover instead.
It's clear to me that you're not knocking other people and their choices here. It's not my intention, either.
Frankly, if you feel you need a catch can, then you do. If you don't want to pay $100-150+, don't.