Your original question, Paul, was about using these multigang extensions for low amperage items. Things have changed in the last couple of decades as regards electrical usage.
Twenty years ago the typical household would typically use electrical sockets for TVs and HIfis, convector heaters, hair driers, the odd radio and that was about it (excluding kitchen appliances(which haven't changed much)). Nowadays, we have many more relatively low power appliances such as phone chargers, cordless phones, laptops or desktop computers, modems, printers, TV set top boxes, games boxes, DVD players, etc, etc.
Our requirement for heat producing appliances (i.e. those that consume a lot of power) has not altered over the years (the world is certainly not colder than it used to be). The thing that has changed is our need for outlets for small appliances.
That is why, provided that the equipment is fit for purpose and not trailing all over the place, we must expect and have no problem with these multigang extensions which meet our needs in the modern world.
Stu