Different experience here. My work app, banking apps, and health apps all easily unlock with TouchID. Love it.
But I have no idea where it would go on a notebook, and with a keyboard right there it does seem totally irrelevant.
Unlock startup screen, electronic payments, fullfill all the passwords on webs... In this last case, it bsically would be like 1Password but instead typing the master password to fullfill other forms and web logins, you'd just unlock it via Touch ID instead of typing.
About where it would go: in the same spot where the old startup button was, there's plenty space there in the actual Macbooks. Maybe if the 2016 Macbooks have the bezels like the new Macbook, it could go on the trackpad itself, there are rumours of Touch ID being avoided in the future to integrate it on the force touch.
And no, it's not an imperative need in a laptop (as it wasn't on a smartphone when they implemented it) but it would be a welcome implementation in future Macs.