I think it might even have negative return. If you do PR in that regard you are going to encourage misallocation of NASA funds. NASA should spend more resources on tracking near-earth objects and less on PR moves like trying to put a man on Mars. Understanding the climate of our own planet better is also an useful target for NASA spending.

Building human civilisation in Alaska is much easier than doing it on Mars. We don't even get things right in Africa where there fertile ground on which plants grow.

Colonizing Mars will need much better biotech and smarter robots than we have at the moment.