It was about the efficiency of two different cooling systems (passive and active) for the entire declared range of operating conditions of the equipment. For your specific operating conditions (and load used), perhaps the simplest passive system is sufficient. Only you have forgotten that the equipment under discussion will be used not only in such comfortable conditions as yours, but will also work in much more severe conditions (in the case and / or with high ambient temperature, etc.). Accordingly, the manufacturer (Khadas) take care not to repeat the previous mistakes and (I hope) strive to develop all the necessary components in advance. Which will ensure guaranteed operation of the equipment in all modes. For those who will use the equipment in light conditions, the first element of the cooling system - a passive radiator-may be enough. For those who will make the most of the equipment-need a second element, a ventilator (with automatic temperature control).
Don’t twist the facts. The difference of 30 degrees I showed you as an indicator of low efficiency of the passive system and high susceptibility to instability at work. Try to place your equipment in real operating conditions, such as in a car (or ATM or other real working device) and at 40-50 degrees of ambient air. And load the system with real work, so that all components (CPU, intensive exchange over the network and with media, etc.) would work. Then evaluate the efficiency of the cooling system.