It is like that this due to the effects of her maintaining her mana. As her kinetic vision and physical ability are superior, she basically evades the enemy’s attacks. The magic mobile armor and helmet being her last line of defense is an important point.
The order of mana pool sizes in descending order goes: me, Armstrong-doushi and Luise.
As for close-combat ability, the order is Luise, Armstrong-doushi and then me. You could call it an obvious choice of role division between the two of us.
“Make it flashy with the highly concentrated mana bullets now.” (Luise)
“Understood” (Wendelin)