That's a fun question :-). Technically it's not, but we're interested in supporting the entire node.js dev experience. One of the advantages of node.js is the ability to move between client side and server side code without switching contexts, so we want to ensure we properly support people working on both.
I also personally get the sense that the lines are being blurred between node and JavaScript (especially now that Npm brands itself as the JavaScript package manager). Curious if anyone else feels that way?
And yeah... You're right... Id be pretty surprised if anyone used node without Npm... Well at least it might serve as an indicator that someone read the question and wasn't just checking random boxes :-)