Isn't the Schulze method superior to single transferable vote? It takes preferences, and it's Condorcet (i.e., if everyone prefers A to B for all B in hypothetical two person elections, then A wins.) STV is not Condorcet.
I can understand national elections using STV since the Schulze method would be impossible to explain to an average electorate, but math.stackexchange is made of mathematicians. Why do we use STV?