The fact that that is the question is what upsets me the most.
If one of two engines fails, chances of the other engine failing are MUCH higer than the only engine failing on a single engine aircraft.
Yes, it is there as a backup, and if it is possible to use it to safely land the plane, by all means it should be done. It's safer for the pilot than the ejection anyway. But if one engine has failed, that means that something is failing on the airplane. The root of the problem might not be in the failed engine, and the failures could easily propagate to other systems, including the other engine. So, an aircraft with a failed engine should be directed away from populated areas, while it is still possible.