To a small degree, yes.
It is designed for heat to escape from all gaps to keep inside cool, but the hinge vent is critical.
Second in importance is the bottom cover where much of the "contact heat" from the logicboard/GPU/RAM escapes, and far less than the heat that escapes through the hinge-vent.
Remeber keeping it on your MBP on your lap while using it blocks the heat escape from the bottom panel. Use on a flat hard surface such as a table. Aslo kind-of safe is a mini-work-table that is hard/flat but has a support frame that sits on your legs for use while sitting (just do not stand up too quickly and dump your MBP).