The Toughness/Crit chances are minor benefits of the professions.
If you were to min/max your toon, either for PvE or PvP progression.
You wouldn't likely include Mining, Skinning or Herbalism on any of them.

The gathering skills are excellent sources of gold, when you don't have much gold.
And they remain decent sources of gold always.

However, you'll generally make a lot more gold from either transmutes or higher end recipes.
Once you have the gold to purchase the mats instead of farming them.
Production from mats (which you just buy) is a greater profit (particularly early in a raid/arena cycle).