Easier to make, especially if you don't have a router. With the right choice of wood (for large Young's modulus) and sufficient neck thickness (!!!!!) it'll work perfectly. I actually expect the stiffness of Rick Toone's hollow aluminum trussrod tubes.
In fact I own three other instruments without truss rods - the two old archtops i restored (where the neck is made of birch for obvious reason) and my 5-string V-bass, where i combined a thick Katalox finerboard with a centre of machiche wood. in an otherwise maple neck. And the tow old maple necks i used in my recent builds are so stiff that i simply do not need the truss rod.