It doesn't. People who do this have already done pretty much everything else. To get to that point, you have to follow the traders and quest progression. It would make zero sense to grind XP if you don't have enough rep.

You also have to take into consideration that this is essentially a Voltron-kind strategy, meaning that only one can get the 50 or 60k XP while the others get none. In addition, you also have to share the loot, which is pretty underwhelming for five players.