Photomatix Essentials RE is intended for high contrast scenes.
A high contrast scene requires taking several exposures to properly render details from both the darkest and brightest parts.
If the contrast of the scene is high, but not very high, then you can still take just one exposure and use Photomatix to enhance it. The exterior of a house, for instance, is a scene that you can often capture with one single photo, even though taking bracketed photos would be better.
However, when you photograph the interior of a house with views out of the windows, then one single photo isn't sufficient. In this case, you will always need to take several exposures, as detailed in the basic technique for photographing an interior.