There are three species of vanilla, all of which grow from a perennial climbing orchid. Vanilla is native to Mesoamerica and was used by the Aztecs. It is the second most expensive spice after saffron because of the labor intensive nature of hand pollination. Vanilla pods are picked green and unripe. The pods must go through a curing and fermenting process before a fragrance develops.
Vanilla powder is made by grinding whole vanilla pods and does not include any added dextrose or sucrose.
While the heat of many dishes will diminish the flavor of liquid vanilla extract, vanilla powder tends to retain the flavor much better, as there is no alcohol -a key ingredient in extracts- to evaporate. It also works well in dishes that won't benefit from added liquid. It is a useful ingredient in baked goods, liquids, and cream based dishes, dissolving easily and imparting a strong flavor. Pure ground vanilla is much more potent than vanilla extract, and cooks should use about half the amount of extract called for in most recipes. Use in baking as a quick substitute for vanilla beans. Some benefits include:
Since they have no water, they can be added to chocolate without causing seizing
They can be used in dry mixes, such as a homemade hot chocolate mix or pancake mix
They can be used in coatings or powders, as for powdered donuts
They have no alcohol, which may or may not make them acceptable to those who avoid all alcohol for religious reason (I am not expert enough to say this as an absolute, because it is likely alcohol was used in their manufacturer to create the extract used to make the powder)