Is it rare for a southpaw to prefer throwin straight lefts, rather than right jabs?

Of course its rare, b/c you absolutely have to throw jabs to do anything in a fight. If you think you can just rely on throwing straight lefts (as a southpaw) as lead punches, opponets will just slip them. You have to use your jab to set up that left straight. All your punches will come off of your jab and double jab. If that lead arm is weaker, you must keep throwing punches with it at the gym to build arm speed and stamina.