I would prefer to carry the lethal option, and would prefer every other responsible citizen of the world to carry one as well. If more good folks with half a brain carried a SD weapon, crime other than thug on thug would plummet.
At any rate, If you need a lethal force option and don't have it, then you could be dead (you were in fear for your life, right?). If you need a less lethal option and don't have it, you more than likely can run. Even if you can't run, what damage is inflicted will feel better when it quits hurting. Who cares if you get a black eye or so? You're alive.
There are certainly times when carrying a less lethal option could save another persons life, albeit someone who is trying to inflict injury on you. IE, the possibilty of using a taser on someone weilding a knife at distance. At any rate, the less lethal option is not required, as lethal force is authorized. Though I believe any human being should use the lowest level of force practical in a given situation, the fact remains that someone is weilding a knife (in this case) against you. If they die because you defend yourself, their blood is on their hands. I would rather see someone have the option to protect their life, even though the odds of needing that protection are much lower than needing a less lethal option.