His reasoning would be that it takes such a small amount for a correct charge that there is more than enough room left in the case to put in a double or even triple charge. If you are observant enough to refrain from doing that, Bullseye is a great powder for light to midrange target loads.
I would like to make a few suggestions. I would encourage you to purchase a Lee chamfer tool, cutter, and lock stud. Then as you purchase dies, also purchase a case length length guage and shell holder to go with these, so you can trim the cases to length.You'll also soon want an inertia bullet puller, tumbler, and related accessories.
As far as dies go, I actually prefer the Lee dies to their more expensive competition. For straight walled handgun calibers, carbide sizing dies are worth their weight in gold, as they don't require lubricating the cases before sizing.