If that's the end user, they're not happy. End users generally don't like doing unpaid involuntary QA work.
And then also it's as you say, customers do need help from domain experts (whether they admit it or not).
The sheer amount of time that gets wasted when people who are awful at expressing what they want just slap together a ticket with little understanding of what they're asking, what the software does, or what the customer wants or needs. Which is far, far too many of them.
Previously, eventually I or another person who does know that would get to it, cross out all the utterly irrelevant parts, strip out the parts that were clearly a completely unrelated ticket, point out to them that they'd asked for the font to be coloured both blue and red simultaneously (neither of which matched the style guide, the company or product colour scheme, or any other part of the UI) and so on and so on... it might takes weeks from start to end for a ticket to actually get expressed well.
Now, the LLM reviews it, adds a whole lot of questions, points out a bunch of nonsense, and sends it back to them. Even in cases where the LLM makes some mistakes, it's 100% fine because the human is forced to think about what they want. The LLM is great at natural language, and it doesn't matter what mistakes the LLM makes.
The quality of the software is going up and up, purely by finally getting a handle on awful requirement and ticket writing.
The human isn't replaced at the start of your sandwich, but now the LLM makes that human do it properly, at speed. Massive, massive reduction in time wasted and significant improvement in software quality.
The problem is that software in corporations has typically been product managers at the front, software engineers in the middle, and QA at the end. Software developers who also have good product sense and do diligent QA are still needed. Programmers who treated their job as leetcode exercises are not needed anymore.