Since designing the production professions to be the most effective when the default skill is maxed out, you (the developers) might want to ensure that it can be achieved regardless of what the player chooses to specialize/focus on.
As it stands, if someone were to emphasize their Knowledge Points in Leatherworking for Embellishments and Armor Kits, they quickly hit a roadblock @ around 90/100 with the only options involving burning 4 sparks to complete the profession.
While it doesn’t annoy me that fishing for skill ups through spamming green Nerubian or Arathi Embellishments, it does perplex me that its designed this way.