Expand the results and you'll see:
It works very well for major regional airports but less so for smaller local centers where there are fewer direct flights. I think the key here is that it is selecting nonstop flights and not considering connecting flights, at least at the moment. Even so, a quick search can provide you with a lot of visibility into what is available and a few queries strung together will likely give you what you need for planning purposes. Of course seat availability and pricing information is not provided but I'd suggest googling before you hit your favorite travel site so you'll at least know your options of times and carriers.
