With the range, sophistication and accuracy of the Enterprise
's onboard sensors, I'm sure they could investigated and taken readings of the ion storm without a crew member having to climb into a "pod" (presumably a bathysphere- or gondola-like device affixed to the ship's hull). It was just a cheap, poorly conceived writer's device to propel the story.
And Kirk's command chair has only what, a dozen buttons on it? Why would one of them control a relatively minor operation like jettisoning a pod?