I was a math major in undergrad, we care about typesetting so much because you really do not want to be stuck handwriting everything, but it's not easy to be faster typing than you are with handwriting when you're writing out rows and rows of equations. (Actually physics was generally a lot harder for me to keep up with while typing than math was.)
And when your life is revolving around classes or your thesis, the #1 most important thing to you in the world is how easily you can transfer your ideas to paper/digital format. It makes a lot of sense that people care a lot about the quality of their typesetting engine and exchange macro tips with each other (I got a lot of helpful advice from friends, and my default latex header was about 50% my own stuff and 50% copied from friends in my same major)
On a total tangent, I found out that my grandfather's university digitized their entire library a few years ago including his masters' thesis from 1948. Back then it was written with a typewriter and by hand for everything else.
I bet he could have done something more advanced if he had modern computers, but looking at it 75 years later and seeing his handwriting on the page was moving more than the content itself.