I initially started writing a response to this thinking the author was referring to preparing lecture notes for lectures they were giving, not taking notes at lectures they were attending. That is entirely different, and I do have to wonder whether it's actually more efficient than, say, using a tablet to draw them, except in cases where the figures involve only use of common, repeated motifs.
I do agree with the author that taking lecture notes for math-heavy classes in LaTeX is quite possible, though I haven't done it since I was an undergraduate. While the author makes use of snippets in a particular text editor setup, I instead relied on extensive use of \def. With sufficient experience and intuition as to when to \def something, I could take notes in many classes faster than everyone writing by hand, and often faster and more clearly than the professor could write: I could insert a common but complicated expression with a few keystrokes, rather than writing it out or using something like ~ to refer to it. I would also use a standard set of \def's to make standard LaTeX faster to type: \beq and \eeq for \begin{equation} and \end{equation}, and so on. This also had the advantage of working in any text editor.
The disadvantage over snippets (I'm not sure how developed they were at the time) was, of course, that my LaTeX was incomprehensible for anyone else reading it, and my style had to change significantly once I started collaborating on projects rather than just writing notes for myself.
I've long used Inkscape for paper and prepared note figures, however, and I've found that many of my colleagues now do as well, after Adobe's transition to a subscription model. In doing so, I am very wary of the pdf+latex export: it doesn't seem as though it can reliably place text exactly, leaving the risk that it looks awkward or has text move when the font; it also makes figures that are not easily reusable in other places (eg, presentations, typesetters making HTML versions of papers, etc). Additionally, the pdf export itself doesn't seem to preserve editing very well. As such, I usually store parallel svg and pdf versions, in the interest of avoiding very non-standard LaTeX packages. However, if I recall correctly, there are packages that allow direct use of Inkscape SVGs in LaTeX.
I do agree with the author that taking lecture notes for math-heavy classes in LaTeX is quite possible, though I haven't done it since I was an undergraduate. While the author makes use of snippets in a particular text editor setup, I instead relied on extensive use of \def. With sufficient experience and intuition as to when to \def something, I could take notes in many classes faster than everyone writing by hand, and often faster and more clearly than the professor could write: I could insert a common but complicated expression with a few keystrokes, rather than writing it out or using something like ~ to refer to it. I would also use a standard set of \def's to make standard LaTeX faster to type: \beq and \eeq for \begin{equation} and \end{equation}, and so on. This also had the advantage of working in any text editor.
The disadvantage over snippets (I'm not sure how developed they were at the time) was, of course, that my LaTeX was incomprehensible for anyone else reading it, and my style had to change significantly once I started collaborating on projects rather than just writing notes for myself.
I've long used Inkscape for paper and prepared note figures, however, and I've found that many of my colleagues now do as well, after Adobe's transition to a subscription model. In doing so, I am very wary of the pdf+latex export: it doesn't seem as though it can reliably place text exactly, leaving the risk that it looks awkward or has text move when the font; it also makes figures that are not easily reusable in other places (eg, presentations, typesetters making HTML versions of papers, etc). Additionally, the pdf export itself doesn't seem to preserve editing very well. As such, I usually store parallel svg and pdf versions, in the interest of avoiding very non-standard LaTeX packages. However, if I recall correctly, there are packages that allow direct use of Inkscape SVGs in LaTeX.