Tephra
14
For a universal counting system, base-2 is the only one that truly makes sense. Base-16 is just base-2 with extra steps because it makes more sense to people already conditioned into the terrible base-10 counting system.
If there are other intelligent civilizations out there, I believe that all measurements will eventually dissolve down to base-2, and 16 is just 4 of those.
However, while base-2 is the most fundamental counting system possible, it is not ideal for normal life where a higher number is better. Base-16 as a base-2-by-proxy would be preferable over the current dreadful base-10 system, but 16 lacks the divisors that 12 has, which is a “superior highly composite number” and makes it excellent for real-life uses.