I'm with Ben here. If you use any kind of automation, tooling, svg optimization, etc .. most times you are going to be using something based on Node.js, so knowing some basics (plus command line basics) will help you a lot. If you are the UI/UX type of front-end developer, then it's less helpful, and you are good with your sass/less/stylus one-line-to-compile workflow.
If you use javascript, and any kind of framework, it's a must!