I'd say the "extra" benefits are:
1. Contains the antioxidant astaxanthin which has been shown to aid in eye health with some research showing it is better than lutein.
2. Strong anti-inflamatory
3. Less/no "fish burps"
4. Most all the same other benefits fish oil has
5. "Possible" lipid lowering and arthritic pain reduction research but not conclusive.
Does that make it worth the substantially higher cost? Up to you, but for me its not. Now, if I had really bad eyes/eyesight then maybe it'd be worth throwing some in. Just my opinion.