"He who controls the budget controls the universe."

The very existence of a budget holder(s) who must at some point get what they are paying for or else they use the budget as a club to beat the team into compliance is precisely why so many "Agile" projects are anything but "Agile". It takes a very unique, special, mature, trusting, and well-funded organization to follow Agile 100% and not fall into the trap of "I need to see something for the money I have signed off on, and I need to see that now" (or similar).

Most teams and orgs just don't fit that description, and it's why Agile is actually not right for most orgs, or if they "do Agile" is looks an awful lot like the traditional approaches.

J.Ja