Gleam Eyes helps bring out weaker Pokemon while you defeat them with Lighting Star, which will help power-up a pokemon such as Zapdos or Raichu. It's a decent combination, plus the low retreat cost helps you quickly switch out Luxray for the powered-up pokemon, such as another Luxray.
9/10 Lightning Star just isn't that useful when a pokemon who can really use all that energy attached to Luxray is available. If it wasn't for that, I'd give Luxray a 10/10. An excellent card right here.