So they found a material which won't degrade in 24 hours due to radiation from the sun, or a way to shield it? And what about the mismatch between the rotation of the moon around the earth and geostationary orbit? And they figured out how to go around the van Allen belts to prevent frying sensitive electronics in the payload? And when the payload gets close to the moon, they have a way to stop it plunging to the surface of the moon for unscheduled disassembly?

Of course the cheapest part of getting to the moon is the bit between the edge of space and moon orbit. Approximate current cost: $0. Approximate cost after placing 40,000kg fishing line in the way....

I'm also pretty sure crawling along a fishing line will be prohibitively slow compared to letting a rocket coast with its engines off.