At work I do not think their use is ever justifiable because the rapidly increase the amount of satisficing behavior from my colleagues. I have had many experiences where obviously bad work was submitted that was clearly llm generated and it was clear that the person submitting it just generated the output and handed it over. People turn their brains off.

The other thing I have noticed about their use is, once you start caring about the quality of your work, their value plummets. If I were to use one for my work I would need to check its output by experimenting with code, doing research, thoroughly considering both sides of an argument, etc. But if I were not going to use one I would do my own work by experimenting with code, doing research, thoroughly considering both sides of an argument, etc. So what is the advantage to using one? Either way I am still putting forth the effort to ensure my work-product is high quality. Going clackity-clack on the keyboard is not the hard part of my job, all the other stuff is.