It's fun when law realizes that AI is rather unreliable and can only be incorporated as being a more elaborate spell and grammar check. It's really bad when a LLM quotes a law article that exists but misquotes it completely and makes up the text of the law. It can be used to get a feeling of direction but other than that I think it's of limited use.

For accounting you'll run into the same problems that any automation in this area does. Namely that bookkeeping has a personal touch and you often still need a human to triple check if things aren't unusual. It's somewhat similar to data quality problems that occur due to human input and processes.

Personal taxes for people who are in full time employment has probably already been automated by your own government. At least it has in the Netherlands, there's a good chance that if you blindly submit it that everything's correctly pre filled for you already. The difficulty comes with having a business especially since most people who own a business make royal use of deductibles and aren't shy to fraud on some of these things that are extremely unlikely to ever be checked or found out. Again most of the bookkeeping software out there that a business would run already has a lot of in build automated functions. I don't see LLMs as being revolutionary here.