You don't run a firewall on your Android devices?
Anything that I'm sure doesn't require net access to function doesn't get it - this includes a clock.
NTP is a good reason for a clock to access the internet...is it not? But I agree on the general gist.
It's set to get the time from the mobile providers signal, it doesn't need NTP access to set the time on the phone - it's how it's worked since before smart phones were available.
If it were the other way around you would never have the correct time if you were international roaming, (unless you're rich and can afford global roaming data charges
Plus the service for accessing the time servers (NTP) is separate (I can individually block it in the firewall), the clock gets the time from the system, there's no real reason for it to be accessing the Internet.