To me the biggest gain I see is that you take the programmers out of the loop. Instead of formulating your ideas to start a project and then acquiring the resources to do a single iteration on it which may take months if not years, now many specialists "just do it" and do several such iterations in a single day. Afterwards they may still go the ordinary route via programmers but on a completely different level and a lot of fruitless work is frontloaded and 100x cheaper. This doesn't show up in any such statistic.

So, the question is not "Does it make our programmers more productive?" but "Does it make our organization faster?".