This reminds me of the early days of Google, when people who knew how to phrase a query got dramatically better results than those who basically just entered what they were looking for as if asking a human. And indeed, phrasing your prompts is important here too, but I mean more that by having a bit of an understanding of how it works and how it differs from a human, you can avoid getting sucked in by most of these gaps in its abilities, while benefitting from what it's good at. I would ask it the question about the capital gains rules (and would verify the response probably with a link I'd ask it to provide), but I definitely wouldn't expect it to correctly provide a comparison like that. (I might still ask, but would expect to have to check its work.)