Somewhat echoing other comments and answers: no, don't think of "mastering" any particular type-setting software, but, on the other hand, yes, it is probably worthwhile to become sufficiently proficient in whatever you choose, so that you do not spend much cognitive energy on typesetting per se, as opposed to content. The particular choice of typesetting system depends on your context, of course, ...
(I myself was coerced to learn some details of (La)TeX in order to satisfy the late-adapter/adopter-incompetence of some publishers in the early 1990s. That is, I "needed" to figure out how to do really-low-level things like move the location of the page-number... This was and is a stupid way to spend time, but maybe unavoidable in some contexts... Similarly, had to have everything sufficiently controlled in pointlessly low-level ways to satisfy the whims of English-major-B.A. editors... so had to retreat from LaTeX to plain TeX to have access to silly things... My advice: do not do any such thing, anymore. Even the heel-draggers have caught up.)
Again, an implicit question somewhat in reaction to "do I have to master...?" is "do I have to have a clue...?", and the answer is "yes". Do not let inability to typeset your work be a noticeable bottleneck.
Another sleeper question: "when you're a novice, should you conform to the formatting and typesetting conventions of the ambient academic culture... or is it ok to get creative...?" :) Well, I tell my own students that conformity is certainly not a high virtue, but it is obviously a convenient virtue, e.g., if one wants to avoid routine dismissal as a crank/crackpot. This is not entirely ridiculous, in fact, I think, since demonstration of awareness of the rituals of a (inevitably, social) group is a positive signal to that group.