I would hardly say it's useless. It's a great ability for when a tank makes a large pull or you want to throw out an Aero III into the mobs or boss fights in general. SS was too taxing mana-wise and the cast time made it useless and even if you applied it prior to the pull it would always break 2 seconds into the fight on auto attacks.

I would argue Plenary Indulgence is the semi-useless button: a fairly weak heal that requires a medica I/II or Cure III for a 10 second lasting proc.

If you don't like a button then just don't use it I guess. :/