One of the most frequent requests we get regarding pool deck surfaces (we're a concrete repair company) is "what can you do to make it smoother", referring to exposed aggregate concrete. If you're a barefoot runner, it's fine, but if the only barefoot walking you do is inside and on your pool deck, it's quite uncomfortable. It's also more difficult to clean, in that it doesn't shed water as easily, which encourages the growth of mold, and it's easier to damage pressure washing than smoother finishes.