I don't trust Square Enix to program worthwhile mouse-and-keyboard controls so I don't know which key fast-forward is assigned to, but I can tell you it's the right trigger on my controller, and that finishing Final Fantasy 7 Rebirth has probably halved the lifespan of that trigger.
Obviously I keep it held in whenever Chadley is talking, or whenever the animation plays because you've activated another Ubisoft tower, but as the game went on I found myself using it even in cutscenes I was paying attention to just to keep the pace up. I didn't want to skip them entirely, because I spent my dozens of hours with FF7 Rebirth suffering from the delusion it would live up to the storytelling possibilities suggested by FF7 Remake—with its promise of an "unknown journey" where anything could happen—but Rebirth is weirdly tame in how often it hits narrative beats from the original game, some of them multiple times, usually while you walk slowly forward.
Everyone who played Rebirth on PlayStation warned me it was full of open world cruft, and it is, but the real problem is that even if you drop the difficulty to easy and ignore most of that, the story's pacing still feels off. It feels too aware of its status as the middle of a trilogy, unwilling to give away answers when it could instead pile some more questions on the pile. It's like if at the end of The Empire Strikes Back you still didn't know who Luke's father was, or what the stakes would be in the finale. It's hours and hours of spinning plates.
The climax is a noisy anime mess: a drawn-out boss fight with one stage too many and an explosion of Neon Genesis Evangelizing where the emotional payoff should be. Things like the dungeon you have to get through by throwing crates at switches are boring, but the finale was what really soured me on Rebirth. I'm not sure if I'd have made it through if I couldn't accelerate it to 1.5x speed at the pull of a trigger.
In retrospect, it really made me appreciate the "wide corridors" approach of Remake. That game let you mess about in sidequest hubs and explorable zones periodically—and slowed you down with crane puzzles and the like—but felt downright zippy compared to Rebirth, which is as overdeveloped as Tifa's chest. Rebirth is enough to make you wish you'd chosen a hobby more respectful of your time, like drug addiction. The fast-forward button saved it for me, and if this is the model for future big-budget videogames I can only hope they let me fast-forward through their hours of doldrums as well.
