[dpkonofa]

That's not how it works. You're the one making the claim, you have to show the evidence to support that claim. They have only claimed that their intention in doing this is to improve security on these devices and they've literally published white papers showing how this does that. There's an entire white paper dedicated to the Secure Enclave and another dedicated just to FaceID.

There's no obvious and direct answer here because you haven't challenged their claim or their evidence that doing this makes these devices more secure because it does. It may have the additional side-effect of making repairs more difficult but if you want to make the claim that their motivation is not what they say it is then you have to provide the evidence for that.