All that I get from this is that you are supposed to choose these weaponskills as the 'next best thing' for jobs that don't get the current best WS.
If you only use sword on PLD, don't bother meriting requiescat, if you only use club on WHM, don't bother meriting Realm Razor. However, Realm Razor on PLD will be pretty good now, especially since Moepapa Mace has more base damage than even 95 Almace or Excalibur. Very good option for vs Bones/Pots etc.