The simple answer to these questions is no, the dimmer can't be used as a remote, nor can it be decoupled. The rotary dimmer must always have a light circuit connected to it, so there is no way to control another device separately from the light ...
The Candeo Modmote can also be used as a dimmer switch with zigbee lights. To use as a Dimmer Switch, ensure that you have paired both the remote and the zigbee lights you want to control. Open the Modmote in the Smart Life app and select Remote ...