Big five terms

Big five terms are great for describing differences between people. But
are they also good for explaining people’s behavior? Is it reasonable to say that “Liz smiled
and greeted people happily because she is an extravert”? Or is that similar to saying “It is
sunny and warm in San Diego this week because San Diego has nice weather”?
In other words, is this sort of “explanation” one that just takes you around in circles?