The #NoEstimates notion has merit in the right domain. If you're looking for motivation for estimates outside of the domain where the customer doesn't really care about the final cost, just the final product developed inside a "level of effort" budget, look here and remember.
When you are spending other people's money - billions of dollars of other people's money - you'd better have a credible answer when they ask "how much is this going to cost and when will you be done? This is separate from "will I get what I asked for?" That's another topic all together.
There are several things we need to remember about agile:
- Agile means paying to discover the requirements as we go. No problem if you know that up front.
- #NoEstimate means you don't have an Estimate At Completion (EAC) other than the passage of time multiplied by the total labor load. No problem if you understand that.
- When there is a budget cap, and deadline for delivery, and a minimal set of useable features, then some notion other than we don't make no stink'in estimates probably needs to be in place.
