[gary-kim]

There are defiantly benefits from having the source code when it comes to being able to verify that the implementation does in fact match the specification. Sure, reverse engineering the binary would be possible but far more difficult. Reading open source code is far easier than reverse engineering. (Added in edit: From what I've read, the spec itself doesn't seem bad. The point is, assurance that does not require trust in another entity that the spec was implemented as written would drastically improve the confidence in the system.)

I have compiled some of the apps on my phone myself so I know that the result does in fact come from the same source code. That may not work in the case of iOS devices, though.

> And you always have the closed source blob of whatever BTLE chipset your device uses which you can mistrust.

That is a good point and it'd be great if that chipset could also be open sourced but one step at a time.

> That would be true even if Apple suddenly decided "oh these folks on HN want to see the code for that tracing component, better open source our complete OS".

You are correct if it was simply open sourcing the OS. If it was possible to compile and install the OS ourselves, that would completely change the game.