So I went here:
https://gaming-fans.com/2018/05/swgoh-understanding-ships-crew-power-in-galaxy-of-heroes/
And found out that ANY level 8 ability (Zeta or Omega) gives 523 crew power (because a level 7 is already 383, this is effectively a change of +140.
Now, I couldn't find the exact relationship between crew power and ship stats, but based off the other, larger increases available for other things (eg a single 3* lvl 15 mod gives +44), I wouldn't say it's worth it, unless you have Zeta materials literally lying around.
EDIT: changed 40 to 140. But I think my opinion is the same, due to the high cost is zeta mats (for most).
