Question: Why would humanity be important to a group of alien races?
Answer: Humans were artifically created beings made to house a Soul or a catalyst. Millions of years ago numerous Great Races made use of the Catalyst to give them great magical and physical powers but they abused it invarious wars that destroyed large portions of the galaxy. The Progenitors punished the Great Races by taking away the Catalyst and creating humans to store them in to keep them hidden and give the Catalyst a chance to live and grow in peace on their own.
Now after millions of years many of the Great Races of died off either through war or through nature leaving two Great Race members, Giant humanoids who are locked in eternal battle for the legacy of the Progenitors. As Humanity is slowly expanding into it's own solar system the presence of the Catalyst has been made known to them and they decened upon humanity in hopes of either swaying them or enslaving them to make use of humanity's hidden power for their own.
another potential answer is that iirc Earth is pretty close to the limit for the size of a planet with a gravitational force that can be escaped by (known) chemical propellants.
So humans are likely to be heavily built by spacefaring species standards.
>>54079126
humanity is actually the oldest self-aware species in the universe
>>54079126
Because humans can be turned into the best mountain dew.
>>54079491
>Mountain dew
>Not Sunny D
>>54079126
Isn't this the plot to Macross with the Zentradi and Protodeviln?