PCs tend to be natural leaders. Or at least, they naturally end up in positions such as when the peasants of the village look to them for leadership against the raiding monsters. Which is a cool way to get them to think about more than just themselves for a bit of a change. So it's worth trying on occasion.
And just because the people consider them leaders doesn't necessarily mean they have all the resources they need to lead the fight.
C-3PO: Luke here is the most powerful Jedi in the Galaxy. He will lead us to grory!
Luke: Did you tell them I'm also the least powerful Jedi in the Galaxy.
R2-D2: Sure, technically.
[SFX]: < whirr foo >
Luke: No, really, I'm not that powerful.
Chirpa: How many smeerps have you defeated?
Luke: None, I must admit.
Chirpa: We have elders who teach us hunting. They can lead us.
Luke: Yes, that sounds like a better idea. In fact, I'm a liability, if anything.
Luke: Vader can sense me.
R2-D2: Oh sure, don't consider any other PC who can lead the battle. For instance, one with military savvy, boundless cunning, and strategic brilliance.
Han: I'm glad somebody is standing up for me!