To learn it?<p>There's a lot of buzz around node right now. And whether you think it's good or bad, having them try it themselves can be a valuable learning experience.<p>Assuming you are a "teacher" of some kind, let them try it, and have them learn the benefits and pain points of it themselves. Ask them why they want to use it, and have them weigh what they thought it would be like vs what they actually got.
You've provided insufficient context to make a hypothesis. However, a possible explanation is that so they can claim some experience with Node.js on their résumé after graduating, since that is one of the major frameworks currently in vogue.