Another ergonomic benefit is scripting. For example, if I'm running a series of scripts to generate figures/plots, LaTeX will pick up on the new files (if the filename is unmodified) and update those figures after recompiling. This is preferable to scrolling through a large document in MS Word and attempting to update each figure individually.
As the size and figure count of your document increases, the ergonomics in MS Word degrade. The initial setup effort in LaTeX becomes minimal as this cost is "amortized" over the document.