In practice
Ask about the past. “Tell me about the last time you did this” gives you evidence. “Would you use a feature that did this?” gives you a guess about the future.
An interview isn't a survey, which collects many shallow answers. It also isn't usability testing, which watches someone use a product.
Why it matters for product builders
A request tells you what someone asked for. An interview helps you understand why.
What changes in AI-first products
Nothing. A useful customer conversation takes the same time it did in 2010. It matters more now because building is faster and deciding what to build is still hard.