It just adds ChatGPT or similar to your sidebar. Chatbots can do a lot of things, they are mostly good for information research and technical help, although they have serious flaws like hallucinating false information sometimes
It is a sidebar that sends a query from your browser directly to a server run by a giant corporation like Google or OpenAI, consumes an excessive amount of carbon/water, then sends a response back to you that may or may not be true (because AI is incapable of doing anything but generating what it thinks you want to see).
Not only is it unethical in my opinion, it's also ridiculously rudimentary...
There's a huge difference between something that is presented in an easily accessible settings menu, and something that requires you to go to an esoteric page, click through a scary warning message, and then search for esoteric settings... Before even installing a server.
Nothing was compelling Mozilla to rush this through. In addition, nobody was asking Mozilla for remote access to AI, AFAIK. Before Mozilla pushed for it, people were praising them for resisting the temptation to follow the flock. They could have waited and provided better defaults.
Or just wedged it into an extension, something they're currently doing anyway.
From the description in the UI, it does sound like it. Theoretically, a chatbot could be created where you can ask questions about the webpage you have currently opened, so if you don't want to read a long article, for example. I guess, you could probably just throw a link into an existing chatbot either way, but yeah, direct integration might be convenient either way.
Well, or a chatbot could be created, which has access to your browser history, bookmarks and tabs, so you can ask it when you last saw certain information. However, you'd need a locally running chatbot for that, which makes it more difficult to implement.