In a way it's possibly more efficient without the heat pipe - the cooler is directly over the CPU in this design, and can be quite large due to the way it's packaged (though it has to be thin).

The downside is it's harder to get decent airflow over the fins. The casing is probably designed to direct the airflow, but I'd have to see all parts together to figure out how this works.

EDIT: the lower case appears to have some ducting on it, see this example: https://www.ebay.co.uk/itm/324259489798