User blog comment:B214/Volume 23 discussion blog/@comment-77.188.220.109-20170502203809/@comment-31137559-20170503190143

Issei was born with the Boosted Gear. Why does he need anything else? Have you seen how strong Issei has gotten in one year? Rias was born with her demonic powers and her POD? So was Sirzechs, Millicas, and Venelana. Vali was born with his demonic powers and Divine Dividing. Should we take those away? What happens when Rias faces Cao Cao and he uses that one ability of his Balance Breaker to nullify her powers? How about when Xenovia isn't able to use Excalibur and Durandal like during her battle against Sairaorg's rook and bishop? She could use a regular sword, but would that be stronger than her two holy swords?

We can get all hypothetical all we want. But we can say basically everyone but Sairaorg is dependent on their inborn abilities, weapons, Sacred Gears, demonic powers, magic, etc. And plus only certain individuals have a talent for magic. Why would Issei use magic when he has his demonic powers? Magic is not up Issei's alley like a hand-to-hand fight is not up Rias' alley. Certain people have a talent for certain kinds of fighting and for others, not so much.