Trying to establish a colony on Mars could be an effective way to develop systems that can support life on a less hospitable Earth. You would need self-sufficient food production systems, habitation systems that are resilient to extremely inhospitable climate, etc. Even if the tech never ends up being used or successful off-planet, it may end up being quite useful here on Earth.

Ok... Let's fly to the moon!!

Look at this puppy - it can walk on its front legs!