Those of you who feel inclined to look back on the events of Persona 4: The Animation, find yourselves here. If you didn't watch P4: The Animation, the series this movie is a complete recap of, you'll be unable to make sense of what you just watched. And for this reason, it cannot substitute watching the whole 25 episode series in an hour and change.
But that's not its intended purpose. While it can be seen as a money grab (profits made from this series will probably go toward the Persona 5 Animation, if there is one), it's just an entertaining review of the series itself.
As P4's plot takes many turns, this movie may help you recollect what happened or explain a part you didn't get.
The selling point of the movie is the aspects that made P4: The Animation an enjoyable watch. The sounds, soundtrack, characters etc. are all in par with the original show. The criticized art style this series has does not improve in the movie the but it doesn't get any worse. If you're used to this art style (which is why I recommend watching this soon after completing the Animation), you should be fine.
Recaps can be discouraging but this one is acceptable. If you really need that refresher course or just have to see everything Persona 4, it's worth your time, or at least some of your time. If you've played the video game Persona 4 and the Animation clicked with you, Factor of Hope isn't a mandatory view but it's your call.