Sometimes it isn't a matter of need, but a matter of want. Almost all the loads i have worked up over the years use Fed primers, and am not interested in rechecking them with other brands of primers.

Even though pistol rounds using small pistol primers show the least variations due to primers, and Winchesters small pistol primers being a good substitute.

Some people may consider buying a case (5000) of primers hoarding, others may consider it extremely practical and cost saving (shipping cost)