It has something to do with, you know, how the lungs and GI tract of land animals evolved such that we breathe and eat through the same orifice and food goes close to our breathing apparatus.
THAT is why Heimlich is important to the evo-debate.
I wonder if whoever decided the this was so profound considered the possibility that the designer considered the alternatives and decided that sharing the orifice, in spite of it's shortcomings, was the best design choice.
The remote chance of choking is more than made up for by the extra breathing capacity the mouth provides when the nose is overwhelmed, or somehow obstructed. The nose is more than just a passage way for air. It also has to smell and filter. The mouth provides overflow capacity when necessary. Great design. Design always involves trade offs, maybe even for a divine designer.