[hawkeye fan asks: "So let's say we do it this way, and there's a success on the Athletics check and a failure on the Stealth check. How would you describe that outcome?"]
Probably exactly how you think: You made the jump, but you attracted the attention of the guards below. This isn't exactly the same thing as having guards on the rooftop because you rolled a complicated success on a straight jump, IMO; among other things, by making it two checks you made the various failure-states pretty clear.
(And if I'm playing that pair of checks I almost certainly take Disadvantage on the Stealth, because being noticed is literally less painful than falling.)
And I don't think there's anything wrong with this approach. It's certainly valid, depending on desired playstyle. I've done much the same thing hundreds of times.
Having some actual play experience with Dungeon World (and having recently read through Ironsworn, which appears to be a much-improved take on fantasy Powered by the Apocalypse that solves many of the problems I had with DW), it could equally be valid to have the GM frame the check as follows:
GM: "You can definitely accomplish the jump across the chasm to the other side of the battlement. However, it's a decent distance, and you're going to have to exert some energy and moxie to make it across without making noise. There's guards posted all along the battlement, and there's absolutely a risk of being heard if you make that jump. What do you do?"
Player: (Probably asks if they can mitigate the risk of being heard, if there's some other plan of action that doesn't result in alerting the guards, etc.)
GM: "Based on the situation and your proposed action --- leaping across the chasm --- there doesn't appear to be much room for error. If you're skilled enough, maybe you can do it; otherwise, your proposed action is definitely going to incur some risk."
Player: (Declares they go through with it).
GM: "Okay, you're triggering an 'Overcome Obstacle' move, using Agility. Make your roll!"
Result: On a strong hit (i.e., full success), no problem; player is on the other side without calling undue attention. On a weak hit (success with complication), player leaps across but can't do it skillfully enough to avoid the extra trouble of alerting the guards.
How is that meaningfully different than calling for two separate rolls? Is it the illusion that the player "still has control" because they can try to mitigate the problematic outcome by having a separate stealth check? What if the GM secretly attaches a penalty modifier to the roll? Has the GM exerted any less influence over the fiction / reduced the player's agency?
Or is it better for the player and GM to have a very clear view of what's at stake when the dice hit the table, and they agree to let it ride?
As a side note, one of the most powerful things I discovered in playing DW (and again reading through Ironsworn) is the notion of having clarifying questions/conversations around EXACTLY what is happening in the fiction. What is the player's position in the fiction? What's nominally at risk for them? What's their status relative to those risks? The idea that it's my job as GM to give the player the clearest possible view of their position resonated strongly with me.