i want to ask exactly what

if(newUser) {
      await clerkClient.users.updateUserMetadata(id, {
        publicMetadata: {
          userId: newUser._id
        }
      })
    }

is the use of above code inside the below code , why are we using it because we created user by clerkid by passing it to server action then why is this IF STATEMENT needed and what happens when i dont use it

why it isnt used in updated user webhook and only create user webhook

if(eventType === 'user.created') {
    const { id, email_addresses, image_url, first_name, last_name, username } = evt.data;

    const user = {
      clerkId: id,
      email: email_addresses[0].email_address,
      username: username!,
      firstName: first_name,
      lastName: last_name,
      photo: image_url,
    }

    const newUser = await createUser(user);

    if(newUser) {
      await clerkClient.users.updateUserMetadata(id, {
        publicMetadata: {
          userId: newUser._id
        }
      })
    }

    return NextResponse.json({ message: 'OK', user: newUser })
  }

  if (eventType === 'user.updated') {
    const {id, image_url, first_name, last_name, username } = evt.data

    const user = {
      firstName: first_name,
      lastName: last_name,
      username: username!,
      photo: image_url,
    }

    const updatedUser = await updateUser(id, user)

    return NextResponse.json({ message: 'OK', user: updatedUser })
  }

@"use php"