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?
That last line is one reason we’re able to fish successfully. Even large fish tire out because they can’t pull enough oxygen from the water to struggle forever.