I still don't get it. It's not exciting to talk about dreary walking through the swamp and rolling the dice 24 times each or 120 times in an hour and a half.
Player: "I rolled a 16."
DM: Ok, that's +1 to the Nature roll. Sally, what are you doing?
Player 2: "I guess I'll try Athletics again."
Well, sure, if you describe it like that, and make it about swatting mosquitos and not dying of swamp fever... sure, not the most exciting thing.
But that's... generally not the goal, here. It's about providing a framework to give ways to resolve more unusual encounters in the swamp. I mean, you describe things that are cool - interacting with NPCs, puzzles, problem solving. Skill Challenges aren't intended to replace those things, they are just another medium through which those scenes can happen.
You encounter a group of lizardfolk. You don't need any skill checks involved, but having some to figure out if can communicate with them, if you can manage to convince them you are friendly, and even persuade one of them to guide you - I see room for interesting things, there.
Or you find yourself hindered by the curse of the Swamp Witch (an ancient fen hag escaped from the Feywild), and the party is wandering through the same region of swamp over and over again. Eventually the ranger realizes he's seen the same broken tree several times. The wizard starts to realize what happened, and they need to work together to figure out how to break the curse and escape.
Or the heavily armored paladin finds himself stuck in a tarpit. Finding a way to get him out - sure, you can just make it about one or two strength checks. Or it can involve finding some well-rooted trees, securing rope to the branches, and then getting him out that way. Or figuring out alternate approaches as well!
Or simpler stuff - the party needs to cross an especially treacherous area of swamp. The halfling rogue tries jumping across via several logs - but looks like one of them is a crocodile! Sure, you can resolve this as a combat instead, but a skill challenge to get around it and calm it down or drive it off (while still dealing with getting across the swamp area)... well, it can often be more exciting than some attack rolls in difficult terrain.
What about the classics? Will-o'-the-wisps floating in the dark. Maybe they lead a hireling astray - maybe PCs are drawn into their lure. This seems the exact sort of extended scene that is ideal as a skill challenge, rather than a combat. I suppose you could reduce it to just a description of what happens, but what is the advantage to removing player influence over the results? Getting out of the swamp faster?
Sure, if you don't find any of these encounters interesting, you can just fast-forward straight to the next region. But if the idea is that there is adventure to find everywhere, I imagine there are plenty of possible encounters in the swamp for which a Skill Challenge seems perfectly suitable to me.