Can/should I use only node with mongo to create simple sites/blogs or should I directly get into building stuff with the MERN stack?

I recently got into NodeJS and setup a few simple sites/blogs with passportJS and all the other "standard" stuff to get a good grasp of it. While checking tutorials and other stuff, I noticed that the MERN stack seems to be the natural next step (other than MEAN which I'd rather not get into for now). Seeing that I can do authentication, get content from mongo etc using node, what exactly are the benefits of combining it with react? I am not really asking about performance etc but more about actual possibilities of creating something. Like what can I do with node+react that I can't do with just node. This is my first question on here so I apologise if anything isn't clear, I am still trying to wrap my head around all the ways of doing things ;)