I've been using AI for some legal issues, and it's been incredibly good at searching for case law and summarising the key implications of various statutes - much more efficient than web search, with direct links to the primary sources it finds.
I'm still the one gaming out "What if...?" and "Does that mean..?" scenarios and making sure the answers are grounded in the relevant statutes, and aren't mistakes or hallucinations.
It's not so much a prompting problem as a critical thinking and verbal reasoning problem.