Familiar Smells and Sleep Aid Memory

We’d have to read the article to get the extent of statistical reliability from the results, but this sounds interesting:

The next day, the rose-scented sleepers remembered the locations of those cards better than people who didn’t get a whiff — they answered correctly 97 percent of the time compared with 86 percent.

We know that extensive and broad associations aid with memory, so are these smells serving as an additional memory cue?