Well, the idea is that sitting TDs come from various backgrounds and it is their background in industries which gives them expertise to propose and vote upon changes.
There can be no doubt that Bertie is a skilled person and a great communicator otherwise he would never have reached the position he did. Tony Blair, the king of spin, has a particularly good word for him in his memoris. Surely it is only natural that he would attempt to use that skill in writing.
But he is becoming a sports columnist. He is not writing about politics are current affairs which is his area of 'expertise'. Can't imagine Tony Blair writing a daily gossip column for the sun or Bill Clinton writing for Playboy!