With transition from lesser to basic conjured items, the need for powerful enough recharging spell become apparent. Not only are two-power items draining energy a lot faster when stuffed with combat powers, but also powers themselves are more hungry. Yes, recharging multiple items via one spell would be a lot better, but such spell is still too weak and unreliable at this level. So recharging ray is a way to go. For now.

See also: lesser chain recharge, greater recharging ray