AI as in machine learning? No I dont think that's bad. It's a very useful technology that we've already been using for decades in a bunch of different fields. But I'm assuming you're referring to LLMs which are what's being integrated into Firefox.

I would argue that LLMs ARE bad. For multiple reasons. At least the big ones run by these giant tech companies.

If you're locally running one with training data provided by you then I don't see an issue with that really. (except maybe energy consumption issues. Though I don't imagine a personal use LLM run locally would draw anywhere near the energy that something like Chat Gpt is drawing.)

I'm very much on the side that believes that what these LLM models do essentially boils down to theft/plagiarism though. So if you disagree with that you may disagree that LLMs are bad.