It is not that hard to identify why talk therapy would help anyone.
Most of us, whenever in distress, feel that yearning for someone in our life with whom we can share everything that is bothering us.
Well, for that, one does not need to seek professional therapy; it could be someone very dear to you who would always lend an ear to your problems.
But talk therapy helps; it really does.

The most important reason is that it sometimes works as a catharsis; you want to put all your emotions out by telling it to someone.
Even in professional therapies, it helps because repressed emotions would always come to haunt you. So it's better to throw it all out.

The most serious drawback of not talking about things may be that unexpressed feelings and traumas can pile up and explode later.

Many of us feel that repressing or pressing down our feelings would not let them hinder our life.
But that's not true. It would instead be exploded whenever something awful would remind you of what you have been avoiding or hiding.

So it is essential to let it all out by speaking to someone; it could be your therapist or a close friend.