This screw head clearly has one purpose: to keep you out. Otherwise, Apple would use it throughout each device. Instead, they only use it at the bulwark—on the outside case of your iPhone and MacBook Air, and protecting the battery on the Pro—so they can keep you out of your own hardware.
I don’t think it’s “diabolical” or even intentionally hostile for Apple to make it difficult to open their tiny, sensitive electronic devices that aren’t supposed to contain any user-serviceable parts.
Think of it from Apple’s point of view: people probably attempt “repairs” on their iPhones and laptops all the time when they shouldn’t — like if they’re unable to do it carefully and properly, which is true for almost everyone — and then they go to the Apple Store, complain that it stopped working, and demand a free replacement.
And for those who could attempt repairs properly, anyone with the ability, budget, and patience to actually get and install working replacement parts for these products won’t have any trouble spending the extra $10 for the special screwdriver from the same vendor.