Really though, level 80 weapons shouldn't be worth any points at all (they can't even use the WS) and level 99s should be worth a lot. Also, xp is severely overvalued by the current system still.
Scholar 49->99
Cost: ~20 hours AFK in a leech party; ~2mil
Point Value: 6539 points
Value: Not really any. I just didn't have time to play and wanted to convert gil into Cruor. 15/15 in NI already.
Twashtar 80->99
Cost: About three months; 50 Itz Scales, 75 Orthrus Claws, 1500 HMPs (~180mil), and 30 Riftdross (~10mil)
Point Value: 0 points
Value: I changed a worthless weapon to one of the best daggers in the game. I use it whenever I am on Thief or Dancer.
I have leveled 6 jobs to 99 in the last week in leech pay cleaves for a pretty nominal amount of gil (most of which I get back through Cruor) and seen my rank jump 80 places. Some of them are jobs I had gear for but no use for (like Beastmaster, Red Mage, or Scholar) and some are jobs that I really just leveled on a whim (like NIN). None of them are worth more to me than a 99 Empyrean, 75 Mythic, or 99 Relic and I can be fairly sure that I'm not a much more useful player now that I have them leveled.
I don't know what the achievement points are trying to measure, but XP isn't worth a ***no matter how you cut it. Purely based on gil and time, leveling a job to 99 should be worth like 500 points.