Journal's inking ability has always been one of the best in the industry. The Application itself has been left to deprecate and much of its stability is gone.
That's seriously a shame, and something Microsoft would do well to reconsider. There is a special place in my heart for Journal, as I spent a lot of time in it as a new Tablet PC user, before I started using OneNote.
As Zhenya stated above, there are lots of times where I just want the quick and easy utility that Journal offers. Also, I am very much tied to a pen and paper. I think a LOT of people are probably like me, where many times I need to feeling of the "boundary" that Journal gives you, with the piece of paper, definite edges, etc. Sometimes it's hard for me to work in OneNote just because it's wide open and free of boundaries. I need some structure.
Also Journal is a
wonderful introduction to inking, for the beginner. As much emphasis as Microsoft now seems to be putting on the pen, Journal is a great way to get people started using it! The menus are simple and the options are limited, but both still give you full features. OneNote is often just so overwhelming to the beginner.
Those are my thoughts, from someone who considers himself a Journal expert and a OneNote power user. I hope you can pass them on sometime.