You all are right that he is just standing on the stage and playing. But he is not a touring member (like Bandiera). he plays on the records. And the band needs him, because a band needs a bassist (unlike lame guitarists who can't play a single solo).
And what his the reason to hide him?? Look at the layout now - it is ridiculous. Four people in the back and Jon in the front middle and Richie on his right and free space on the left. I don't see any little reason to do this. I kinda understood why they changed it for LH tour - they said they needed to balance it. But now?? they did the opposite!! I really hate changes lke this. They played for ages in a classic arrangement and from one day they need to add lame musicians and change the arrangement before every tour. I this meant as a breath of fresh air??? It would be better if Jon started to sing for a change...