@katharsas
While you are correct in that most people using a thing doesn't imply that said thing is better than any alternative, it does say something, especially when those people are experts in their field.
In fact, I'd say that experts are, by their very definition, typically correct about most things covered by their expertise. Sup Com is no exception to that.
Luckily for us, expertise in Sup Com is very easily quantifiable. Every game and tournament is public, resulting in a binary outcome.
Similarly the opinions of the 20(?) or so FAF pros is also quite accessible as they are all active community members (albeit some more vocal than others).
So when all of the experts do something essentially the same way, e.g. they all use the (mostly) default icon set, it's a strong indication of that being the 'correct' way to do something.
In the absence of further evidence I'd say that just copying what the experts are doing is the way to go.
Of course, experts are not infallible. In the light of new results, their opinions, like any other, should be challenged. This is what I am doing with this thread.
This does not mean that their opinions should just be ignored though! In fact, for something hard to measure like "icon clarity in high level play" their opinions are probably the most important data points we have!
Or in short: Don't discount the experts just because you don't agree with them. Even if you think they are wrong, you can still learn from them