There are a lot of different things to be interested in. At one end visual/graphic design is interesting because, like engineering, it's seeking optimum performance among constraints. Neue Hass Grotesk might technically "outperform" other specific fonts in specific contexts, enabling you to find, say, a restroom at the airport faster and with less effort than if the sign were in Fraktur.

On another end of it, there's the recognition that what often starts off as efficient or economical in one context will form a cultural symbiosis with that context, carrying it around for decades or centuries to follow. That's why Cooper Black might remind you of cheerful commercialism from the 70s, but it also explains how seeing Eurostyle on a fried chicken menu will give you a very specific idea about how much you'll be paying and what the condiments will be like.

In between, there's "crazy lizard brain stuff" like the Bouba/kiki effect: https://en.wikipedia.org/wiki/Bouba/kiki_effect