The WHO is a coordinating body. They don't exist to tell anyone anything new. They didn't "tell the world that there was a pandemic". They formally declared tha

The WHO is a coordinating body. They don't exist to tell anyone anything new. They didn't "tell the world that there was a pandemic". They formally declared that the pandemic fulfilled the criteria to be officially recognized as such. Maybe you don't see any use in that, but someone who needs to plan for the event of a pandemic probably appreciates it that they can simply write "if the WHO declares a pandemic" and rest assured that this will happen if and only if there's actually a pandemic.