Once you start giving out the Carbontwines

[Ophie-Mio]

For the same reason raiders want 130 gear, it's not mandatory to complete final coil either, but you still want it.

Because want that fat ilevel. If they cared about stats, their current gear would be a mix of poetics, WoD, and FCoB gear. I personally care more for stats than ilevel but to a PF, seeing someone advertise that they are i130 looks better than me saying that I'm 120. Most of the time, they'll want that person instead even though I may be far above their skill level.