The typical configuration of hypsilophodonts is that of an herbivorous bipedal dinosaur running swiftly through the underbrush and nibbling at the leaves on the forest floor. Marsh's original interpretation was the opposite; he envisioned a small carnivore rushing around the underbrush snatching up small mammals and insects. However, he also envisioned Laosaurus as a tail dragging bipedal carnivore, as was the norm of many paleontologists in the 19th century. Tail dragging eliminates the ability of any animal to jog off into the underbrush of a forested canopy. The sub-rectangular head is full of teeth that, while they could be used by a carnivore, are far more likely to be found in the mouth of an herbivore or an omnivore; some of the teeth would be fairly out of place in the mouth of a carnivore.
A more horizontal position for the spinal column is also a little more pleasant to look at as the upright Othnielosaurus looks a little too rigid for a living, moving animal. An Othnielosaurus that is somewhat bent over can forage a little bit faster and is already in a pretty good position to sprint off to safety with very little notice. The ability to sprint with little notice is important for a dinosaur that has very little natural defensive ability outside the ability to bite at would be attackers, as any animal with teeth can do.