Resources humans need are here on Earth; why travel to Mars?

We know more about the surface of Mars than the bottom of the ocean, or so I hear a couple of times a year. I don’t know if that’s true, but it sounds believable because we see more news about space. Space is a wonderment; we can see it from anywhere. The bottom of the ocean is covert, covered, we can’t see it, even though it is a lot closer. The heavens seem close, because we can see a lot of stars from almost anywhere. Most of us only see the edge of the ocean. Or the top. Where the water is very clear one might see the bottom 600 feet down. Most places you are lucky to see 6 feet down and the average depth is over 2 miles. There is twice as much of Earth’s surface under water than above.