Estimation discussions, in my experience, have one very valuable outcome. It's not the story points, but it's the conversations and interactions that happen around the story details. As the team builds familiarity with the user context, business goals, existing framework, technology options, assumptions, and so on, there are valuable ideas that take shape.
Breaking down a user story into tasks (or things to do) helps the team align on the best implementation approach. The pros and cons of an approach are discussed. The trade-offs (what we will not get by following this plan) are discussed. Assumptions are challenged. Risks are identified. Ideation kicks in. The most important outcomes from an estimation session are these ideas, tasks, and questions.
So, if we flip this around, and conduct implementation discussions instead of estimation sessions, then we can expect that estimates will be just one minor detail to derive. We saw in Chapter...