There's really no guarantee that it will work well enough to minimize your water changes. Think of it this way, saltwater systems are ultra low nutrient systems filled with live rock which is basically the same thing as the denitrator coil and still have big issues with nitrate levels. Even something that removes as small as 1ppm nitrate per day is going to be a huge benefit to a saltwater tank. So what I'm saying is, it'll probably help but don't expect miracles. Plants really are the most reliable way to remove nitrates.
That being said, I might be completely wrong since I've never personally used one. The only way you are going to know for sure is to just try it out.