[wonderwonder]

If we colonize mars, and reach the point where we have a full fledged society there it can act as a means of quickly recovering from a catastrophe on earth. The benefit of a fully functioning city/nation sending resources to assist a ravaged earth would boost earths recovery time if the worst were to happen.

Secondly, it acts as a separate bed of innovation. On earth we solve for earth problems, on mars they would solve for different problems, potentially leading to scientific and tech breakthroughs we would otherwise overlook.