TV's and plumbing are still measured in inches in the UK, the measuring system was already in place when we went metric and it was what people were used to. Plumbing fittings are as you said now rounded off to millimetres etc. but the actual physical size is still the same as the original imperial. For example what is referred to as a 25mm fitting is actually one inch (25.4 mm).
There were no monkeys when dinosaurs existed, also more time elapsed between the stegosaurus in the back existing and the t rex and triceratops than between them and us.
We are kind of unique in our ability to sit on chairs, the majority of animals throughout evolutionary history have some form of tail.
Imagine we meet aliens and every species is incapable of sitting on a chair, it'd make start trek look a little foolish.
TV's and plumbing are still measured in inches in the UK, the measuring system was already in place when we went metric and it was what people were used to. Plumbing fittings are as you said now rounded off to millimetres etc. but the actual physical size is still the same as the original imperial. For example what is referred to as a 25mm fitting is actually one inch (25.4 mm).