As far as high level code is concerned Apple's chips are just ARM chips. They've got microarchitectural features that put them ahead of other ARM chips clock for clock. But if you want to call their implementation obscure then by that twisted logic then AMD chips are obscure because they operate differently than Intel chips despite the AMD64 ISA.

It's a stupid distinction to justify an ignorant statement. Between iPhones, iPads, and Macs Apple has shipped a billion of their CPUs. At a billion units it's just dumb to suggest they're obscure. Different from Wintel PCs? Sure. But obscure? That's just asinine.