Garuda Normal mode is was useful if you had a less than stellar group, it prevented a wipe as you moved into P2.

If your group has a crappy ilevel of weapons (what the damage on SMN/BLM/DRG/MNK is based on), then its usable in Titan/Ifrit/Garuda if you are low on gear but high on skill, as it is a % damage reduction. Meaning, if you don't anticipate dying due to the boss being alive for too long, you can use the tank limit break to not wipe on a jump or hellfire or whatever garuda does. However, if you are geared, the melee limit break is almost always more useful.

Its probably under used due to over-valuation of the melee DPS limit break, but its still pretty worthless.