I'm a fairly senior developer and I use it quite a lot. I think 3.5 can do most of the things you need most of the time, but 4 and the API's help you save a lot of time. It's not really world changing in that it's still not very good at actually writing code that couldn't be auto-generated before LLM's, but it's just sooooooo much more efficient at doing all that auto-generation than what you had available before, and with the API's it integrates fairly seamlessly into many IDE's. Just remember to deny it access to any code that's actually secret. I work in the energy sector, so we actually has some of that, but 90% of what I've worked on over the decades could've frankly all been open source with not great issues. But again, it'll depend on what you do. If you're in HR, contract management or similar, you'll probably not be able to share much of what you do with it legally.

But like I started out saying, get your company to pay for your subscription if you use it for work. It's a tiny fee compared to a lot of the other money your company already spends on you.