Memes

Humans and earth's biosphere are valuable simply by existing. Since complex life is very very very very rare. Alien xenobiologists and evolutionary scientists would have an great interest in studying and observing earth.

It is a fundamentally flawed approach to project human thought patterns onto aliens (human reality itself is limited by its own methods of observation), biological reality shapes ideology. BUT it can still be deducted that any alien species advanced enough for interstellar travel is curious and pro-science and so would find xeno-ecospheres valuable.