Scenarios:
1) Your baby, toddler, kid(s), and/or spouse/friend/mistress are missing. Only way to find out is from the location stored in an iPhone from the suspect - which is also dead. Sorry folks, can't help you because we can't decrypt.
2) codes to diffuse a nuclear bomb is stored on an iPhone and it's encrypted. Can't save the world because we can't decrypt it.
3) The last message written by your dad before he suddenly died was written on his iPhone and encrypted. Sorry, can't even have you see his last words because we can't decrypt it.
4) Child porn of your kid(s) stored on an iPhone but encrypted and not stored in iCloud either. Sorry, can't prosecute the perv because we don't have evidence we need from his iPhone. It's encrypted, we can't decrypt it.
5) Car accident and you were not at fault because while you were driving you were also v-logging with the iPhone clamped on the dash and someone hits you and the camera caught a pic of the accident but obviously from the accident your head was injured enough you can't access your code (the phone was off (battery drained) then restarted so the passcode is needed). You're screwed.
6) Before a police officer was murdered, he was recording himself and the camera on the iPhone caught the sounds and part of the suspect killing the police officer. The phone dies of low battery but the video is on the phone and encrypted. You can't prosecute the suspect because the evidence is on the phone.
7) the list goes on and on.
Now if you argue that oh, I want to prevent mike who works at the FBI from eavesdropping or looking at my personal naked pictures I took while drunk, then of course you're trying to make a case about your privacy. I think the point of encryption is to protect the owner but then there are times when you hope and pray that you can access it because the one you loved who happened be have evidence on the device is no longer here and it's crucial to gain access to it but you can't, then you can see how desperate one will want access.
This is very hard to decide....