Yes, and no.
While it can be extremely helpful to have someone in your corner cheering you on, it can also be a distraction.
Let me explain. You have your writing buddy and you’re reading each other’s work and everything’s going great. But then your buddy gets stuck and can’t seem to focus. They lean on you so much that it affects your own writing. That’s where the problem comes in.
I am all for having a writing buddy. Just make sure there are clear and well-defined boundaries set up in advance so both people know their role and what the other expects from them.