@ICWiener,

You are correct, the local control option was removed last year in the Kasa 3.0 App Update as it was only ever an added feature and was not technically within the intended design of the devices. It is worth mentioning that this is actually only in relation to the setup of the device. Once linked to your TP-Link ID, the devices can communicate locally with your phone and do not need to be connected to the internet if only being controlled locally.

This was done for a few reasons, but mainly so that we can make sure that your device is delivered firmware updates. You will begin to see more as to why this feature was removed over the coming weeks, as linking the device to your TP-Link ID looks like it is allowing for increased compatibility and features to be added. 

I would recommend looking to see if your home network has an option to isolate devices on the network or removed their internet access, as this would allow you to quickly toggle the connectivity if a firmware update ends up being needed, or the time needs to be synced.