[codeplea]

That's a good point. I think efficiency is desired because it usually provides fairness. In an inefficient market, trades are at the "wrong" price, and so that seems unfair. When there is a trade-off between inefficiency and fairness, we seem to prefer fairness (e.g. insider trading laws make the market less efficient but more "fair").

[yellowstuff]

Matt Levine of Bloomberg writes a lot about how insider trading laws seem to be about fairness, but are really about theft of information from the rightful owner. It's hard to square a market centered around fairness with the vast informational and technological advantages that professional traders use legally.