It just seems like it would be a really cool thing to have gills and be able to populate the oceans in the same way we populate the land. We could have houses and shops and vehicles, andgo on walks/swims and just kind of live underwater.
Start a whole new second species of human here on earth maybe, Who knows?
Its funny I did a paper on CRISPR in highschool and was very interested in the technology and one of the possible uses I mentioned was giving people gills to live underwater.