It is "hardly worth mentioning." JTB is a common sense theory.
JTB is a common sense understanding, yes. I don't think anyone is denying that knowledge should be justified and true in order to be considered knowledge.
The problem is the practicality of application. Truth is a moving target: it changes with our own understanding. Justification is even less solid: who is the objective judge who determines whether something is sufficiently justified or not?
It all boils down to our own personal and collective mental calculations. When we are certain that something is true and sufficiently justified, we will consider it knowledge. Certainty (of truth and justification) is therefore the defining factor, and not actual, objective truth and justification, since none such "Platonic ideals" actually exist.