It also means you can't use the display to turn the controller on / off. The controller will need it's own hardware switch or else be hardwired to battery positive at the keyswitch/ignition wire.
The display also cannot monitor the system voltage, because it will have to have it's own battery in order to cut down wiring, and AFAIK the displays measure the voltage there at the display--if they receive that as data from the controller then that part isn't applicable to your situation.