Ya know, this Zoan Smiles is actually more powerful and dangerous than I initially thought.
Momonosuke accidentally ate one of those smiles and turns out to become a dragon.
That was pretty much a mythical kind of zoan, right?
So this means CC was able to produce a myth zoan there, therefore I can assume it may be possible to create a phoenix as well (another myth zoan)? Or any other myth zoans that you can think of.
And what's more, Momo was able to fly, an ability granted only to a small handful in the OP world.
Though we have yet been informed about any weaknesses of Smiles, but the ability to fly itself is already quite an advantage in combat.
Assuming that Smiles (being an artifical DF) are not bound to the singularity rule of a standard DF, can you imagine the said Yonko's army made out of 100 Dragon Smiles or 100 Phoenix Smiles...
How can a standard pirate crew fight against such army?
If my interpretation above is correct (or at least near correct), then I can finally see how this weapon could have shaken up the NW (as Law mentioned back then when forging alliance with Luffy).
The above was not correct as the artificial DF that Momo ate was created by Vegapunk, not Caesar.
Then again, Law said he wanted to use this special weapon (SAD) to take down a Yonko with Luffy. And recently we know there is already one Yonko having a Smiles army. So its either:
1) Law wants to build HIS own army of Smiles and take on a Yonko (could or could not be the one with a Smiles army already), or
2) some user predicted SAD needs to be fed to Smiles-users constantly, therefore in cutting the supplies of SAD will render the Yonko (with the Smiles army) weaker and thus makes the challenge (fight against a Yonko) easier.