OK, so, Middle Eastern people will already know what I'm going to say, so this is for Westerners : this is huge. Not just because Gazans are calling to kick out Hamas, but because it is a assembly of CLANS.
For Westerners, clans are seen as, in effect, an outdated concept that doesn't really have that much weight, so why care. You'll have some famillies that still hold up their clan structure to a point, like when three or four different branches of the same familly gather at the same place at set dates with some degree of regularity. But overall, the idea of "clans" in the West is seen as something of the past, a piece of folklore.
That is very much not the case in the Arab world. Clans still play a major role, socially AND politically. Clans are a very, very, very important part of someone's social identity. So if the Clans of South Gaza are calling for an Intifada against Hamas, then those clans' fighters will at minima be given an unofficial ultimatum : Hamas or the Clan, quit one.
Will we see flashy consequences on TV ? Most likely not, Hamas is from the same cultural sphere and knows the social rules and context. But it DOES show a loss of faith and trust in Hamas, and also a loss of strength sufficient that the Clans feel comfortable attempting this. So Hamas won't be able to just slam a foot down on that.
My point being : this is huge in the Arab cultural context.