Like any business, WWE must get value for money on its investments. The fact is that Sheamus is one of the top earners, pocketing a million dollars a year. For a long time, he was in the main event scene, but then dipped out due to injuries and the return to a one title system. WWE have been keen to get him back involved for a while, hence this year's image and character change, alongside the Money In The Bank and WWE Title win. He's now in a much better position for WWE to get a return on the money tied up in his deal. From the company business point of view, it made sense to run him as a champion.