Beginners, start here. Yes, that's something of a tautology.
One of the many tasks of the proper subeditor/copy editor is, to use the technical term, cut the crap.
It may be invidious to pick out an individual. John Harris, of the Guardian, is merely another of the countless exponents of "added bonus".
A bonus is "an extra and unexpected advantage", says the Oxford. Since the meanings of "added" and "extra" are synonymous, young JH could have saved himself five keystrokes by simply writing "bonus". And many more in future if he follows my advice for most of the times that he writes "bonus".
Deliberate deployment of tautology is best left for the poetic, eg, the "bosky wood" of Rupert Brooke.
Tautology is likely to be a recurring theme in these pages. One of my favourites is "ruling military junta", which can invariably be rendered accurately as "junta". Well done, the Wall Street Journal and no end of others.