Well, it's terrible at factual things and counting, and even when it comes to writing code it will often hallucinate APIs and libraries that don't exist - But when given very limited-scope, specific-domain problems with enough detail and direction, I've found it to be fairly competent as a rubber ducky for programming.

So far I've found ChatGPT to be most useful for:

1. Writing SQL. Seriously, it's fantastic at writing SQL if you tell it the relevant schema and what you're trying to achieve.
2. Brainstorming feature flow - Tell it the different parts of a feature, ask for thoughts on how the user should be guided through the process, and it does a decent job of suggesting ideas.
3. Generating alternative names/labels for buttons and such. "In X feature, I have a button that does Y when the user has Z. Currently I have that button labelled 'Start Y', but it feels robotic and impersonal. List 10 suggestions for what such a button could say to be more personal and friendly." and the like. My favorite was a button that was labelled "Map Incoming Data to Job Details". Wound up renaming the whole process to just "Job Ingestion" because it sounded so good.
4. Reformatting data. Give it a data structure and tell it you want that data in some other data structure, and it is really accurate at reformatting it. I don't think I'd trust it with a huge amount of data that way, but for an unimportant one-off it was a nice time savings.