I'm still convinced this is an excuse to bring Touch ID to a Mac, and to allow for more secure login. I don't think the Touch Bar is useful for people who are already adept at not looking at their keyboard. But who knows...
I was under the impression that Touch ID is actually less secure than a sufficiently complex passcode/phrase. It's certainly easier to find a good fingerprint from someone than it is to read their mind and extract a password.
Security measures are defined around threat models. People worried about the government getting access to their electronics probably won't rely on Touch ID. People worried about their stoner roommate using their machine can probably rely on Touch ID.
Especially since a password can't be forced out of you by the government, but they can force you to touch your phone. Touch ID is not protected by the Fifth Amendment, apparently.
The flip side is that entering a strong password is tedious and incentivizes people to use shorter, easier to type passwords or disable / increase the time delay for things like their screensaver locks.
That means that the question is really whether Touch ID is more secure than the passwords which people will actually use in practice. As criddell noted, how you answer that is going to come down to threat models and resources. Biometrics really put you into some pretty different trade-offs: e.g. a camera can record you typing in your password but not your fingerprint, but someone can force you to touch the sensor or maybe pull it off of a glass, a password can be faked safely while someone watches you but that fake fingerprint is much riskier, etc.