The purpose of the document to assist users of food color in determining which format may be best for their applications. Dyes are water soluble, but will not mix with oils.
Lakes are dispersible in vegetable oil and thus can be mixed with fats, etc.
A little goes a very long way. Granules basically have a larger particle size, and thus do not have as much of the dusting problem that is associated with powder dye. Granules are usually more expensive than powder. Trying to add powder dye to a batch of molten candy will result in specks of powder in the finished product. Every shade dye has its own unique peculiarities which may be affected by other ingredients, the dispersion medium, temperature, pH, dye content, and the manufacturing process.