A pistol is always available...
Provided one carries it all the time. That is the main point of 'superiority' if such it is.
One can invent or think of various scenarios wherein a pistol would be of greater utility than a longer arm, but they are specific and few. A longer arm can normally be employed with greater precision and distance than any handgun, under the same conditions.
Or to put it in other words, If I knew I was going to a gunfight, I'd take a carbine at a minimum.
For a person who's business is getting into other people's business (law enforcement, for instance) one would hope the individual agent would have both options at his disposal - pistol on hip, long gun in the transport.