Because you’re using an external device to extend the capabilities of the port. It can’t do that without the dock, so now you have two things to carry around.
If you look at the comments on this, there are two distinct camps of people who will never agree: those who expect their laptop to be a self-contained unit that doesn’t require anything that wasn’t packaged with it to meet common use cases (which requires more ports), and those who are okay with docks and dongles and adaptors.
Because you’re using an external device to extend the capabilities of the port. It can’t do that without the dock, so now you have two things to carry around.
If you look at the comments on this, there are two distinct camps of people who will never agree: those who expect their laptop to be a self-contained unit that doesn’t require anything that wasn’t packaged with it to meet common use cases (which requires more ports), and those who are okay with docks and dongles and adaptors.