The porous qualities of ceramic allow the paint to seep into the surface before lying on the surface; left at this stage it has a dry, rough appearance and a more natural ceramic like feel. When more paint is layered on the surface it becomes like any typical substrate (wood, etc.).
Ceramic also holds heat longer than traditional painting substrates and this allows more working time. More working time keeps the encaustic soft and pliable; allowing you to manipulate it in ways that become difficult when it has cooled (see alla prima). Objects can be shaped and later attached, glazed traditionally or painted with encaustic. Relief, texture, and writing are just a few things that come to mind.
There is also the question of high fired versus low fired clay. Personally I have used both low and high and found little difference in encaustic; however, more often than not low fired is recommended.
