The only good reason I can think of it that this is just a temporary plan for her to get you to open up more, so that you'll be able to open up more in therapy. Maybe she's reading your journal and getting a sense you need to talk more about something in the moment with her so she can understand it better?

But, it is a bit off seeming. I've never heard of a T suggesting you not write about your feelings, not to mention encouraging contacts out of session. In my mind the fact she reads your journal on her own time, on top of the therapy time, seems somewhat off as well.

This would worry me, and I would ask why she feels like this will be helpful. Not sure.