There's truth to the ScrumFall design process which is inevitable for most development processes. It's not just that a tool needs to be marketed, but that it needs to be integrated with work from multiple teams and other processes. What ScrumFall does is provide some level of feedback prior to delivery. In the age of Waterfall, devs would develop until they said they were done, we'd get to delivery and UAT only to find that key features work differently than expected and continually extend the release date by months or years until it finally goes out the door more from frustration than actual completion. That stress level would be pegged at 10 for months until it was completed.