The big void is where our future inevitably lies. The ocean is really interesting and can help us answer questions about our past, and how to help future generations make the Earth a more sustainable environment -- but we're not moving to the ocean one day. If we don't kill ourselves before the sun consumes the Earth, the oceans will boil away and then we'll have to go to space to find a new home. If we start investing in space research and exploration now, we'll have either terraformed something or found a new home to live in. And they'll probably have some cool oceans to explore there, too. And then maybe one day, on that distant planet in the future, a guy will log onto the internet and make a post on a forum asking why people care so much about space when we could be exploring these cool oceans we don't really know much about. And then maybe a guy will point to the big expanding ball of fire in the sky and remind them that we need to escape that thing one day.
Also, space is really interesting and looks cooler