Also dev what's the difference between lyra2 and lyra2-zoin? why create a different flavor? When I check the Lyra2 code, I don't see any differences though.
The Lyra algorithm is the same, it just uses different parameters. Originally ZCoin had unsustainable parameters for Lyra, as explained here:
https://bitcointalk.org/index.php?topic=1671060.msg16863305#msg16863305If ZCoin didn't change the algo, it would have needed more and more memory and got slower and slower until most machines would not be able to do the hash.
Zoin had to change the original ZCoin algo for this reason.
It's nice that Zoin improved ZCoin. Why do we use Lyra2 here at all? Any adavantages? Would it be the same to use scrypt or X11 etc as PoW while still keeping the zerocoin features?