It’s mostly replaced search engines for me, at least for the initial part of research. I still ask for and double check citations for anything important.
I frequently use it for work (computer programming), making example images of a rough concept, translating to different human languages, having it perform a deep analysis where it searches and summarizes multiple sources, formatting Markdown and other text, etc.
I also use it for fun, generating trivia questions or using it like a smarter Wikipedia to learn about new concepts, summarize PDFs (though NotebookLM is better for that), talk about cats, and other inane stuff like that. More examples from other threads here: