That is true. The Apple Watch can unlock macOS using the security chip inside the Mac, but that requires a charged, Wi-Fi, and Bluetooth-connected Apple Watch, which can add friction to some users.

The fingerprint sensor, however, is almost frictionless, as secure and responsive.

I guess the best solution would be Face ID, which doesn't exist on the Mac, but I hope Apple brings that tech in this year's WWDC event.