Question

List key reasons for the popularity of LaTeX.

Answer 1

In LaTex, you need to set it to work on a file containing text interspersed with code and it spits out a Postscript file that another program can convert into a PDF.

Many scientists and mathematicians write articles in LaTex form:

as they type the words and punctuation marks of the text that the reader will encounter, they intersperse them with bits of code that instruct the computer on how to type these texts.