Most electronic devices use 3.3V, 5V (all USB devices), 9V or 12V (very often for electronic music gear), and we usually all have dozains of such wall adapters at home. Even desktop computers have usually 5V and 12V power supply (ATX power supply).
Is there a historic reason (or electronic reason) why laptop computers are usually around 20V?
Why don't they use a quite standard 12V?
Linked question: Why is a laptop power supply output voltage different from its battery? but here a bit different, I'm not looking for the reason about the voltage being different from the laptop's battery, but rather why it's different to the standard 5V / 12V used in desktop computers.