The design of the Boeing 737 series right from the original 737-100 was planned as a two pilot operation that did not need a flight engineer. Various cockpit system switches were automated because, by the then certification rules, if the cockpit design meant that more than (say) 100 manual actions including eye scan was needed, the rules required a flight engineer. Hence the 727 needed a flight engineer. One small example of the automation in the 737 was the no smoking/seat belt signs. Set them at auto and forget about them. Automatic changeover from auto-pressurisation to standby mode is another example. Automation has just saved perhaps 8 switch and /or eye scan items.
This suggests that the more additional switch operation the pilots choose or are required to undertake for local SOP reasons (and by definition superfluous to Boeing design philosophy), the more is the two-pilot certification compromised. You can flick the volts and amps as much as you like - whatever turns you on I suppose - but the fact that these actions are not mandated in the Boeing manuals as a specific part of cockpit drills, suggests (IMHO) certain switch checking is superfluous to the operation of the aircraft. Every action, however minor, causes a work-load increase - hence the two pilot certification rule that limits the number of actions before the flight engineer claims back his position in society.