If you use it in a "what should be done" or "what is the right thing" sense, you get useless generalities. "It is important to remember that ... ". Suppose for example that you talk to it about combating judicial bias. It will largely insist that judges are unbiased because they're supposed to be unbiased according to their job description... You won't walk away with any insights from engaging it in ethics/morals topics.
If you dive into depth with some subject, it will invariably make errors and contradict itself in the details. I dove into how electricity works and it was saying and enthusiastically confirming electrical energy is encoded in electrons' kinetic energy. Then it started claiming that electrical energy is definitely not in the kinetic energy of electrons, that electrons don't lose speed when they bump into atoms, and instead the energy is "in the field". Ok... YouTube it is.
It's at least less convenient than a search engine at routine fact-finding due to its knowledge cutoff, inability to display images and links, etc. Ditto with translation. It's good but so is Google Translate and Google Translate has in-line suggestions for misspellings, a menu of languages, etc.
Ok, it's pretty good at writing hilarious poems, imitate people ("in the style of", etc.). Friends and I sometimes text each other hilarious things GPT said. But even there the machine is sort of laid bare, and you can see its creative limits. Its poetry is ultimately pretty lame, basically, and gets predictable. It's like an insistent and repetitive 8 year old with a lot of knowledge to pull from. It's not something I do often.
It's good at writing boilerplate code but honestly I just don't reach for that use case often. I like to stay in my own flow rather than constantly delegate to a robot and check its work, which I find flow-breaking, especially if it doesn't understand my APIs and makes mistakes often.
I do, sometimes, engage in architectural discussion about how I should design something at a high level. It's full of mistakes but bouncing ideas around can be useful. But I only feel the need to do that once in a great while.
These issues are exacerbated by being forced to downgrade to 3.5 after using 4 for a bit. You might feel like you're getting somewhere with 4, and then 3.5 starts laying doozies on you. This is another UI/product issue, but affects usability.