I'm pretty skeptical of the market argument - reading the linked article, it seems low granularity subsidizes market makers when there are many small orders (which often get worse prices than they would otherwise) and this subsidy allows market makers to be deeper, which subsidizes large orders. Which is a difference, but not an unalloyed good.

Surely price competition is more economically valuable than the queue position game, which is measured in economically meaningless nanoseconds.