The reive in ra'kaz have a high enough amount of HP that they give several evaluations before they fall, and you can also get useful high tier simulacra pieces, its pretty much the new 'fishbotting' for people to afk make gil. Bayld (hp bayld) is terrible gil/hr so people have resorted to this to make ergon weapons also.

The reive also have enough out of aggro range on them that you can freely attack them with mage job.