Easy to achieve, just saying. I duo'd Omega pretty casually (WHM+BLU), and farmed all the chips solo with ease on BST.
If he is in a shell that does Limbus (or Neo-Limbus), he possibly does not have soap available to do Limbus on his own. Buying the body allows him to get it without using any soap.
If I had to wager a guess:
He is in a group that does Neo-Limbus regularly, and he has gotten Arch-Omega's heart from the group, but does not have Homam Corazza yet. He wants to be able to sit in the zone and buy the body if it drops to save his tags.
Alternatively:
He does not want to waste 4 days to farm an Omega pop because his time is better spent elsewhere.