We have that thread every Raid, but people still keep asking if its worth buying or not, and the currencies vary slightly.
So, this time:

The 10% Moogle is 30000.

assuming you didnt grab 5 Barbies in your dailies (F2P, what else), and RnG is neither generous nor cruel, we can anticipate something like 1500-2000 currency per ELT run if you use a strong carry and 5 bonus units: 2 3stars, 2 4 stars, a 4-5 star friend (or FIEND muhaha), Gremlins included.
That means you will need 15-20 ELT runs at 25 NRG, being
375-500 NRG
If youre Lv 100 you will have 140 NRG for 100 Lapis, resulting in potential NRG of
525-700
The good old earth shrine gets you 5,25%-7% (RNG-dependent) for 5 units.

So what else can you do with that currency, Trust wise?

Brilliant Rays
Being a Bonus part of 3 S-rank expeditions, 2 being a moogle, and i'm always broke on these. lets break that down:

100 currency for a Brilliant ray
You can buy the full stack instead of the moogle (30000).

I know its a pretty ridiculous comparison, because you dont get these expeditions every day, but let me try. 10 Brilliant rays get you 20% Bonus on the 1% moogle expedition. That means 1 Brilliant ray equals 0,02% Trust. we got 300, Thats 6% Trust. again, only for ONE unit.

TL;DR
* Buy the moogle if you want the instant 10% for a specific unit (or if you have the 30000 already)
* Spend the NRG on Earth Shrine runs if you have the spare time, thats better.
* Buy Brilliant rays only if youre short on them.

Happy Farming!

EDIT: u/Greensburg: If you macro, don't do S-rank Moogle expeditions, a 1% moogle is only worth 20 nrg. Might as well just do two C 12h mission for two energy pots and save the gil/materials.