The closest earth gets to Mars is between 60,000,0000 and 100,000,000 miles. We are 239,000 miles from the moon. So it is like traveling 2.39 miles and saying it is a good jumping off point for a 600 to 1,000 mile trip.
I don’t get it unless leaving the moon’s atmosphere is so much easier than earth however, even so, you still have to get all the supplies to the moon.
It gives you the chance to work out the necessary skills 3 days from home, before you launch to Mars, 3 years from home. Like making a few trips to Canary Islands before heading off to the Indies.
It’s NOT the distance that is the advantage! It’s ESCAPE VELOCITY and ENERGY requirements to achieve that velocity.
The distance is merely a mathematical variable. It does not matter much in the equation....................
Gravity.
Maybe Matt Damon will set them up to grow potatoes?