Ecklonia Cava is a type of seaweed which is known to be one of the highest sources of phloroglucinols, a type of antioxidant compound that appears to be unique to sea plants. The phloroglucinols appear to be very potent anti-oxidants, and these benefits have been noted after oral ingestion as well.
That being said, the potency of Phloroglucinols being anti-oxidants seems to be a bit separate from the magnitude of benefit one gets from ingesting these compounds. Benefits have been noted on blood pressure, blood glucose, and inflammation but for the most part these are statistically sound but practically small benefits. The current human evidence is unconvincing for the most part, although these compounds and seaweed are undoubtedly 'healthy' as a general statement.
Other effects that seem interesting for Ecklonia Cava are an apparently anti-allergic potential that is not highly explored, and there appears to be some anti-cancer properties as well (mostly tested in regards to melanoma). Topical application of Ecklonia is one of a few compounds that can enhance hair growth, and it appears to be novel in the sense that it both inhibits androgen-induced hair loss and also directly enhances hair growth (so it, by itself, appears to be some form of combination therapy).