Isin's way of using casual events as a means of crafting his characters is clear of the rest bc of how subtle & organic it is. Hitagi learning how to drive on her own means that she's mentally prepared to be invested in a hobby for herself & her bf shows how far she has come from

Bakemonogatari and how she overcame her trauma that drags her down with by loving Araragi, which led her to warm up to herself.

This is a consistent method of storytelling applied in Monogatari that's used throughout it for many characters like Hanekawa, Hitagi, Kanbaru, & Araragi. A few more examples would be Araragi's storyline with the stone in KoyomiMonogatari, Hanekawa's ingredients scene in SS, etc