Not trusting apple with keeping their promise they won't share the finger print in the future is a good reason.

So you're saying you're worried about apple pushing a malicious iOS update because they want your fingerprint?

If yes, this feels utterly nonsensical. They would be able to grab your fingerprint from the sensor anyway, whether you are actively using it or not...

Alternatively you might be spreading some weird conspiracy theory that instead of securely storing a "hash" of the fingerprint on a HSM, current touchid implementations are secretly sharing your fingerprints with Apple.

That's not really any less nonsensical.

How anybody can still use this argument after prism is beyong my understanding. Literally. I do mean i can't grasp it.

What argument? It’s utterly ridiculous that you would assume Apple to be incapable of collecting your fingerprint data simply because you didn’t enable TouchID in their software.

Do you just not use the home button?

If your password gets compromised, you can change your passwords.

If your fingerprint gets compromised, you CANT change your finger (erm... probably. I dunno of any easy way in any case)

It's not your fingerprint that's the issue, it's the data that represents your fingerprint. If that data gets compromised then it's nigh impossible to change your fingerprint. However, I believe there are ways to make this very significantly difficult, and I believe Apple has achieved this level of difficulty by placing the fingerprint data in the secure enclave.