Not using colors in scientific writing is discarding a valuable information channel and therefore inefficient. When you are already limited in the allowed word count, this can speed up conveying information and reduce cognitive strain on readers (and possibly yourself). So it’s a win-win.

This should not end in chaos though, where colours are more confusing than helpful.

The times when we had to print out each and every single page on a crappy black/white office printer are luckily becoming more and more a thing of the past. So even this is no longer a good reason to not use colours.