Here's why:

* A compound machine is made up of two or more simple machines working together.

* A watch uses many simple machines: gears, springs, levers, etc.

* However, these simple machines work in a complex, interconnected system, rather than distinctly separate units.

Therefore, a watch is technically not a "compound machine" in the strict sense. It is a complex system of simple machines working together in a highly integrated way.

You could argue that a watch is a complex system of simple machines that work together to achieve a common goal, making it a functional "compound machine." However, this interpretation is not universally accepted.