LR offline use?

Yes, Lr can be used offline.

Obviously sync will not work until reconnected. Also some features are disabled, the AI search for example. The ability to rename albums. Most of the features that do not work offline are noted under the feature in Victoria's book: Edit Like a Pro book: https://www.lightroomqueen.com/shop/ 

I have yet to see any information from Adobe about what works offline, but to be fair to them, I stopped using their help system a year or two ago.

Tim

Hey, It's not silly.

Yes you can use it offline on a particular device but you would not be able to transfer your work as well as settings to other devices.