For me the journal is just an outlet at the time of distress, i don't feel the need to discuss it in session and in fact, by the time session comes i can barely remember what i wrote. So it's not that important, but it is perhaps useful that she reads it to get a feel for what i'm thinking at the times of distress.
I think she is trying to bring focus back to the work in the room but since we never discussed the journal (that was never the intention of it) then what i wrote in it never took attention away from the session anyway. All that's changed is now i've not to bring the journal in and as a result she won't know what's going on outside of session.

So either she's doing it a) in the hope that i'm going to store up all that emotion and bring to session and produce art work or B) in the hope that when i feel bad at home rather than writing in the journal i contact her and allow her to help me