whenever you use alpha, the triangles of a mesh are "unsorted", this leads to the well known z-order artefacts.
As long as you don't need semitransparent parts you should use Masks instead, the have no z-order problems. When using DDS with alpha information for masks, they are still simple masks, only DirectX will utilize the alpha info to draw an interpolated outline.
BTW when you load a texture with the alpha flag and the texture doesn't contain specific alpha information, then the darkness of the pixels are used to set the transparency level.
As long as you don't need semitransparent parts you should use Masks instead, the have no z-order problems. When using DDS with alpha information for masks, they are still simple masks, only DirectX will utilize the alpha info to draw an interpolated outline.
BTW when you load a texture with the alpha flag and the texture doesn't contain specific alpha information, then the darkness of the pixels are used to set the transparency level.