I answered yes. The past few years have brought JS modules from npm as the way to do things. jspm and bower both require and use Node and are distributed via npm... Most of the time you can "just use npm" as npm, private and git based modules are all supported.
Beyond npm are common tools for composing client side applications. Less, sass, browserify, Babel, webpack, gulp, grunt etc. All of which (except for sass) are Node (cjs module) based, and even sass is available as a nice module, using the c library and faster than the Ruby one.
Node modules also tend to use a consistent error-first callback pattern. Now things are changing. Promises for callbacks and es6 syntax for modules via Babel are becoming the norm.
You should understand all of the above, and that's a large part of what Node is... Beyond a fairly small set of modules for io, crypto, and network services.
This is why you should know these things... No, you may not need to know how to diy a server in Node, but you should understand the tooling and core concepts Node used as most of the js community has already moved in that direction, even for client side builds.