[rini17]

There are inherent factors, though.

1. Any time you mix motors and electronics, motors produce brownouts and spikes which can cause directly connected electronics to malfunction. DC-DC converter mitigates that. LEDs are particularly prone to overload with just minute increase in voltage and dim/flicker with decrease.

Not inherent to DC but same thing happens with poorly designed appliances that emit RF which then interferes with everything connected to the circuit.

2. Voltages. You can't standardize electronics power supply to 12V because semiconductors are most efficient at lower voltage, which depends on particular technology.