There isn't usually a difference between sea view vs.ocean view, but there can be a difference between ocean view and water view. This can occur in places that are close to the ocean but also have other bodies of water, such as a bay, lake, or river.
The Pacific Ocean is the largest and deepest of the world ocean basins. Covering approximately 63 million square miles and containing more than half of the free water on Earth, the Pacific is by far the largest of the world's ocean basins.
Generally, Deluxe means full ocean view, versus partial. If you are booking through the Ilikai Hotel site, you can see the descriptions there. In my experience - deluxe has meant a higher floor - more expansive view. Often quieter.
Whether you choose an oceanview or balcony cabin should come down to two primary considerations: price and itinerary. Can you afford the extra money you'll pay for a balcony? Or, even if you can afford it, would you prefer to spend that extra money on some other cruise experience (drinks, shore excursions, the spa)?
There will be no shortage of prospective renters or buyers down the road looking for a great place to vacation or retire. Beachfront real estate is a good long-term investment, whether you decide to rent it out or use it as a family vacation home.