It's a little bit spendy for how much damage it prevents (3+card for 6 damage), but it does "stack" with whatever else you have going on defensively, so it's a nice backstop to keep your Dauntless active in the event the villain's boost cards don't fall your way, or in case you take some surprise extra attacks from an encounter card. It's also a damage prevention card you can play while you're not in Hero form, which is nice if you're running Meditation or other forms of Alter Ego economy.
And the combo with Repurpose (conveniently in the same hero pack!) is pretty spicy. Absorb 4-5 damage with the energy counters, then mulch your Forcefield Generator for a ready and a sweet +3 to one of your stats.