What are the advantages?
One of the benefits of kief over other methods of making hash, including butane, propane, ethanol, and even water, is it requires almost no equipment and has no safety concerns. For consumers who don’t like the idea of chemical solvents, kief stands alone as a supremely natural method of concentrating cannabis, dating back several thousand years to hash-making locales like Morocco and Afghanistan. Even water hash can get moldy and could constitute a health risk if poorly-made… but kief is basically idiot-proof, in that you’ll always get a safe product that is stronger and more pure than straight-up marijuana.
If you want to go one step farther, you can also press your refined kief using light heat and get something similar to a shatter, which can be easier to work with than loose, dusty kief.