I put that there to silence the additional logging of the error by `task.react` which distracts from the Eliot output above. 
It would also be nice if there was some way to signal an exit status to `task.react`, and that errback would be where I'd choose the correct status. 
I found these tickets mentioning this idea:
 * https://twistedmatrix.com/trac/ticket/1490#comment:46
 * https://twistedmatrix.com/trac/ticket/6159