Can a smart switch work as a conventional switch?
Unfortunately, the answers to both of your questions are almost certainly "No".  

As far as I can see, that system (like many other similar ones) does not run the power wiring for your lights to the switches.
The power for the lights runs to the control box(es) and from there runs to the lights themselves.  

The switches are wired to the control box(es) using much smaller signalling/communication wiring - so the switches themselves do not see or handle the 'real' switching of the power to your lights.  

Removing the control boxes leaves you with no power to your lights, and the only option you'd have is to simply bridge across where the control boxes were - resulting in your lights being always on.

You can't replace the smart switches with dumb switches because the switches and control boxes have a communication protocol which they use to talk to each other. The control box wouldn't know what the dumb switch is trying to tell it with a simple on/off signal when it's expecting to see a complex 'language' over the wire.  

Unless you want to go through with the exercise of completely re-wiring the switches (replacing the small-gauge signal cables with larger power wires) you're stuck with this (or another similar) 'smart' system.  

FWIW I design &amp; program commercial smart lighting systems like this for my day-job...