Why do I need to have an AI or a player controller possessing a character to have Root motion work?!

I have an asset in the scene that needs to have a root motion in a BP, it is not a player character nor an AI driven one. I spent 3 hours not knowing why my root motion was not playing, until I discovered that I need to have “AI Controller” or a player controller enabled in my BP to have it working. I had disabled them for various unrelated reasons prior.

Can someone explain why do I need to have either of these enabled for Root motion? AI controller will spawn needless AI controllers in my game when I don’t need them, and my asset is an NPC in the game that has a looping movement that you can’t interact with. Why does a controller need to possess a character for root motion to work?