Confidence intervals are great. The important thing is that they should get refined and narrowed over time. As you get further along, you should become more confident about the delivery timeframe.
I think this practical execution piece is often lacking in estimation processes. If you only deliver a confidence interval once or twice over the course of the project, that's not useful. If the interval never changes, that's not useful.
https://tech.lgbt/@risottobias/112373995567079983