I live in the UK, so I'm aware our power sockets have switches. However, if I walk into a darkened room I certainly don't want to crawl around in the dark looking for a switch - so better that (as I believe a friend's home has in some of their guest bedrooms when I had reason to visit) there's an ordinary light switch, near the entrance door at a good height - to activate the distant socket.

Since you live in the UK you may also be aware that, unlike ordinary appliances, smaller low power (5 amp) connectors are authorised for lighting, so in that particular house because of its age the floor lamps literally can't plug into a conventional socket, the plugs are the wrong size, this has the further advantage that you can't accidentally plug an appliance such as a vacuum cleaner or television into a socket controlled from a light switch.