Dof Object should allow bones as target

When you set the Depth of Field target for a camera it only supports objects.

Wouldn't it be nice if it was expanded to include bones as a subtarget if an armature was that object? (just like with parenting)

This would mean you could animate it as part of a camera rig. At the moment the only way is to create an empty object and then parent the empty to the bone that you want to target as the Dof Object.