Of course, epoxy is stronger than Titebond, but I've never had a wood joint fail at the joint in nearly 40 years of woodworking. It fails the wood before it fails the glue, so in the end the glue isn't the week point anyway.
Having said that, Titebond III, though slightly less strong (and still way strong enough), is also waterproof, and as noted cleans up with water. That should be plenty good for the ribs. If it's a main load path with high local loads, then epoxy would likely be preferable, but even then, probably not mandatory as long as there's enough strength that the bond-line is not the weak point it should be fine.