There’s a short but snappy article here, about the benefits of using personas inside user stories as part of an Agile project.
The killer paragraph is this:
“it’s much harder to write a rubbish user story when it’s grounded in a persona. Let’s face it, there are plenty of user stories in most of our backlogs that are really management feature requests disguised as a user story. Transform your backlog so that the user stories that are supposedly there to help the users are given to a persona and suddenly it becomes much easier to interrogate feature requests against real users.”
This is entirely, absolutely true. It is so much harder to add additional features if they cannot be tied back to actual people. I know from personal experience that as development draws to a close, you find last minute requests being added, and the rational is very weak, to say the least.
Using personas will force people to justify everything as a requirement against a person, not a process.