Just a wild guess: To maintain faith in the system? I don't know anything about Compound aside from what I've read today but I would imagine whatever you've got

Just a wild guess: To maintain faith in the system? I don't know anything about Compound aside from what I've read today but I would imagine whatever you've got invested could quickly go to zero if the crypto-investing public decides the protocol is too risky. (Assuming, of course, there exists an upper-limit to their risk tolerance.)