Alright, you're right - it is part of the spec. Non-standard is the wrong terminology. My point being though, Apple tends to be ahead of others in terms of adopting (for better or for worse) new standards, and their influence in the market can sometimes make those changes happen at a spec level (i.e. tell ARM they want a new instruction, and magically it'll be in the spec).

The original comment's point is this would be good for the RPi org... which use comparatively ancient ARM processors (even the brand new RPi4). I don't see how Apple entering the ARM space on desktop is relevant at all.