Impact is spread over time and multiple vectors. So now you have three problems in addition to getting working code the door - prioritising proposed features based on estimates of value, finding accurate metrics for assessing value after release, and mapping value changes over time.
The nice thing about feature-driven-development is that it avoids the hard work of having to understand what you're actually doing.
You can make the hamster wheel spin really fast and persuade yourself you're really going places.
I have no data to back this up but I'd say the majority of projects I've worked on during my career my time would have been better spent working on things that made the development teams more efficient. That is to say, with rare exception, I don't think the software actually generated anywhere near the benefit it cost to develop and maintain.
The nice thing about feature-driven-development is that it avoids the hard work of having to understand what you're actually doing.
You can make the hamster wheel spin really fast and persuade yourself you're really going places.
Until the wheel falls off.