The US uses many smaller circuits. I have two appliance circuits, a lighting circuit, a dedicated refrigerator circuit, and a 240V range circuit. Five separate electrical circuits, just for my kitchen.

Rebuilding after WWII, the UK standard was to run a single ring circuit for each floor of the home. They ran as few household circuits as possible, because they needed the copper.

If you look at the amperage/wattage ratings of UK circuits, they are considerably higher than other 220v/240v countries, because their circuits are intended to be shared among many more devices.

You know how they warn you not to plug in too many devices into a single circuit? The UK electrical system took the exact opposite approach, because they needed to. This is why they have a fancy plug that nobody else in the world uses: it is an essential safety component that serves the same purpose that the household circuit breaker performs for the rest of the world.