Amp doesn’t have standby so I keep it off and hooked to a WiFi power surge programmed to shut off at 2 AM and on at 9 just to be sure if I forget. Previously CA and DAC were always on standby but recently I got a Wiim pro plus which goes in standby after two minutes.
The main benefit comes with the fact that with a Chromecast audio, a wiim or a raspberry pi your mobile device act as controller, not a player. This saves bt compression and battery life on your phone/tablet.