Agreed. The ability to stop the plane was not in doubt (landing distances are not predicated on thrust reversers.) The immediacy of the problem - engine failure with fire that took longer than expected to extinguish and smoke in the cabin - made LGB a viable option.
Also, looking at the flight track, they were already on a wide downwind and would have required a time-consuming course reversal and vectoring to get to LAX. They made the right choice to get it on the ground ASAP.
BTW - who here would not use the full 10,000ft of runway in an emergency?