I think the question is less about whether or not a "correct / valid use" of this new technology is acceptable. The problem is that it's impossible (once it exists) to guarantee it won't be used in malicious ways.
It's not like iOS is impossible to hack now and it would be terrible that it becomes possible. There are other aspects of the system that allow malicious exploits more easily than this theoretical threat. So it doesn't make sense to preserve at all costs (e.g. making warrants unenforceable) an "impossibilty" that never was.
No, not really.
> Or is the ability to comply with a warrant worth nothing?
What if I issued a warrant for you to give me a 3 headed dog? Is your inability to comply with a warrant worth nothing?