Nah koby was quite litearlly a temporily crewmate for luffy, can't say the same for smoker
Coby was never a temporary crewmate for Luffy. Luffy always knew he was going to join the Marines and made no attempt to convince him otherwise. Meanwhile he was set on getting Zoro to join up with him.
I think the begrudging alliance between Smoker and Luffy in Punk Hazard and Alabasta is far more likely to resemble Roger and Garp teaming up against Xebec than how Coby treated Luffy in the first few chapters.
Kuzan is whining about koby being garp protege, also pretty sure there's more narrative importance if garp new student avenges garp death from his old student
Coby has a strong relationship with Garp. Smoker doesn’t
Smoker has a strong relationship with Kuzan. Coby doesn’t.
Basically, if Kuzan kills Garp, the thing that will upset Coby the most is that Garp is dead.
The thing that will upset Smoker the most is that Kuzan is the one who did it.
I don’t think either Coby or Smoker will need to actually fight Kuzan and avenge Garp’s death. If Garp dies because of this, Kizan will justify it as a sacrifice Kuzan was willing to make for an overarching goal of taking down Blackbeard.
Remember, we know the Blackbeard’s openly don’t trust Kuzan. And it’s not like they deliberately stepped out to capture Coby and set all these events in motion, it‘s basically been thrown in their laps by chance (or fate, as the Blackbeard’s are more likely to see it).
This is Kuzan’s big test to the Blackbeard Pirates. If he doesn’t give his all, they know he’s false. And if he does give his all in these circumstances, then he can get them to accept him and drop their guard.
For Smoker, though, it‘s the biggest part of his development, which has always been about his black and white world view. He’s seen Luffy isn’t all that bad, he’s seen a pirate can infiltrate the Marines, now he’ll have to face his friend and former commanding officer apparently turning into the worse type of pirate- despite being reassured by Kuzan that he was still the same person. That’s a personal betrayal, due to the relationship between the two. Coby and Kuzan don’t have a relationship, so it’s not personal in that sense.