You should use whatever experiences have really driven your motivations for a legal career in law. It doesn’t really matter what the experience is, it’s more about explaining how’s it’s shaped your motivations. Therefore, you could use your work experience or the event you attended, or even both.
For more commercial questions that are asking you to analyse a topic, it is important to bring your own thinking to the answer. Although you can reference things that the firm has done in this space, it’s really important to show your analysis rather than just repeating the firm stance on the topic.
More candidates are likely to reference or repeat information about the firm’s strategy in relation to AI, and you are risking not standing out from the crowd if you just take the same approach and let what the firm is doing being the core part of your answer.