The secure enclave is a feature to secure the device and the data on it from casual threats. Apple gets a bit evasive any time the subject of security shifts to their cloud services. (i.e. they will talk about how a particular feature is e2e encrypted but their security talking points seem to mostly end at the device)

I think a better way to look at what they're selling you is a device that provides you pretty-to-very good protection from casual hacking and theft. But in the event of a government knocking on their door for more information, they'll quietly hand over what they can which probably is quite a bit more than the average consumer thinks it is. All bets are off as to what the full story is when the government/jurisdiction involved is not the United States.