Well it's a bit more difficult, but you could let the organisms themselves decide who to mate with. Or you could have a smarter genetic algorithm that keeps sufficiently different organisms and tries evolving them for a few generations and see which type is superior.
There is really no advantage in speciation if you only want the single best solution, but it does make sense to try different evolutionary paths as they can end up in totally different places.
That's a bit of a weird assertion. Genetic algorithms are always a greedy heuristic to find a solution for a problem. It is not guaranteed at all that it will find the single best solution faster than straight bruteforcing solutions.
If speciation is a better heuristic for finding a better solution faster than the algorithm used here then its advantage is real and useful in any case.
What I meant by that dividing the population has a cost. Only one evolutionary path is going to end up with the best solution. By best I mean the best one you find, not necessarily the most optimal solution possible, which may never be found.
If you divide the population in two, at least half of your resources are wasted on doing tests and evolving traits which will just be discarded. Resources which could have been used to speed up the evolution of the other population. Even if the evolutionary path you choose isn't the optimal one, by putting twice as much resources too it, it still might end up further. And if you divide it into more than 2 species than it's just getting insane.
That's not to say that speciation isn't a useful heuristic, just that it's a costly one. However there are a lot of cases where just throwing more resources at the problem doesn't help, because it's stuck in a local maxima. In that case, going back to an earlier point in the simulation and running it to see if it ends up somewhere else isn't a bad idea, and that's exactly the same as what speciation is (except that you are doing it after the fact, rather than testing both evolutionary paths simultaneously.)
There is really no advantage in speciation if you only want the single best solution, but it does make sense to try different evolutionary paths as they can end up in totally different places.