They aren't needed. Especially for a diver from Louisiana who rarely needs to worry about frozen regulators (lucky), free-flowing regulators aren't much of an issue unless you routinely drag yours through the mud or otherwise abuse them.
They are effective at blocking air flow to a free-flowing second stage, but in the event of a free-flow from the first stage they may actually be dangerous. The low pressure hose between the first and second stage isn't designed to take a high pressure load, block that flow and the hose or the fittings may burst with violent results. Most failures occur in the first stage.
They're a mechanical device and add yet another possible failure point, increasing the likelihood that you'll have some kind of problem.
I thought Apeks had stopped selling these things. They only cost beer money, but better to spend the money on beer. In the meantime, go ahead and learn how to reach back and turn your valve on and off - a good skill to have, even for single tank divers.