A level of competition is good, because it makes people do their best. But as soon as it becomes too cut-throat, resources are wasted on auxiliary things beyond just being the best and most cost-effective.
These electronic trading boats would be an excellent example of "market failure" in this regard.
Instead of actual trading boats to trade their food and stuff, we'll now sit in the middle of the ocean to correlate some arbitrary signals... Like excessive speculation in commodities, it doesn't add value.
Don't tell me "it adds liquidity" because I already know that. One could argue we have massively enough liquidity already in the things that would actually be arbitraged here.
The financial sector overall is much too big: http://www.voxeu.org/index.php?q=node/6328