Disease and hunger will be ongoing for as long as we continue to be human. If it's not cancer or hunger it will be something else.

Interplanetary travel is very obviously the next logical step for mankind. This doesn't have to come at the expense of biotech or medicine, and in fact would probably enhance it and accelerate discoveries across all fields of science and technology.

Just how much of a window do you think we have on this planet? It's not a free ride forever. At some point whether tomorrow or 1000 years from now things can and will go very wrong. We were not the first dominant species on earth and it's more likely that we won't be the last.