For humanity, the only advantage was that the enemy's missiles had to climb the gravity well before they could attack the mother ship. It was just unknown how strong the enemy's industrial capacity was and how many such super rockets they could manufacture…
"It must be very strenuous. Otherwise, the enemy could easily produce dozens or hundreds of rockets and launch them all at once, leaving humans with no possibility of interception."
This kind of inference also made sense; rockets hundreds of meters tall could weigh tens of thousands of tons. Such powerful weapons of violence could not possibly be mass-produced in a short period of time, so there was a good chance that humans could catch their breath for a while.
