Pellets are more weight & volume consistent than brass powder measures housing loose powder & those brass powder measures (5-120 grains) are what most shooters use when pouring their favorite powder/powder substitute out of the jug.

Having said that, I shoot loose powder 100% of the time. Pellets are 1/3rd more at the cash register than loose powder & I can afford to buy them, but I'm afraid that once I buy the first box of 100, I'll be hooked. Also, since I use 110 grains 777 loose, that means I need (2) 50-grain 777 pellets and (1) 30-grain pellet 777 to match the velocity/energy of 777 loose powder.... which is 15% more powerful than 777 pellets.