Most modern electronics (as in laptops, game consoles and smartphones) support dual voltage and frequencies but their default plug type is region locked, so if you’ve bought a PS5 in the UK importing it into the US (the default cable is Type G that comes with the packaging when plugging into a TV) unless you swap cable for a Type B plug but it’ll work fine.

And most appliances are designed in such a way that the swapping is extremely easy - no soldering, just unplug the bad one and plug in the good one. And this secondary plug is so effing standardized that you probably already have a suitable cable lying around.

Why is there no unilateral plug type that’s “region free” when discussing plug types found in appliances.

The EU plug is one attempt. I believe that includes the UK.