What role do you see fear playing in NPCs via video games? Outside of the occasional "scream" or "run away" I can't think of a time where I've seen fear utilized deeply via gaming NPCs
Video games don't have NPCs in the same way. They have scripts.
The key distinction being that the purpose of knowing their wants/fears is to know how they should respond as unforeseen events unfold. Real RPGs have unforeseen events. Video games have branching, but highly deterministic, events - therefore, the "NPC" just needs a set of scripts that cover those branches. You don't need to predict anything. They don't need to be characters in the way that RPG characters are characters; they need to be characters the way that fiction characters are characters.
The old sharecropping farmer may fear his landlord squeezing his finances in the fall.
The greedy merchant may fear that her husband is pissing away too much money on drink.
The cobbler's apprentice may fear his boss, because his boss is a huge, sometimes violent asshole.
These fears can add background flavour through worldbuilding, that make these characters memorable. Nobody cares about, or remembers generic merchant #2 in Bumtown, Nowhere, but they may remember if their first introduction to her is walking in to a family fight about liquor.
Even if the players never explicitly discover that fear, this grounds your design of the characters into something more interesting than "He's a farmer, she's a merchant, he's an apprentice."
I think its less about making scenarios about their fears and more about their motivations. If you know what they want and what they fear, you know what drives them to do the things they do and you can come up with responses or scripts that tie back to either a means of getting something or avoiding/preventing something they fear. Fear doesn't have to be something tangible either, but something like loneliness.
Its about creating deep, relatable (or, at least: understandable) characters, that make the world feel more alive and not just a dull response dispenser.
Long ago when I dreamed of writing a game, something that bothered me was that people kill characters they shouldn't and the flavor of the game never changes. In games where NPCs try to escape, they forget that you just tried to murder them. If they catch you skulking, they don't become vigilant. If they hear someone being killed in the next room, nobody comes, nobody hides, nobody runs.
When the mayor of a town has been killed 500 times maybe the townspeople should be deeply xenophobic. Maybe the shops stop selling weapons, etc.
Pardon the tangent, but this was particularly blatant in World of Warcraft. Because of the quests, you basically spend half your time committing genocide (wiping out some species or group). For some quest lines you have to murder your way into a place and then murder your way out of it. The irony of this is that the quests turn rogues into the least murderous class in the game, by far. They are the only ones that can reliably sneak in and out instead of murdering bystanders. This is disturbingly backward.
The other irony is that many of the main storylines are about preventing genocide. If a genocidal maniac goes around killing all the other genocidal maniacs, is it because they are good or because they are eliminating the competition?
In dnd, when you want a NPC to go your way, you can do them a favor, persuade them or intimidate them. If the players discover what the NPC fears, they can play on it. So basically, in videogames, it could offer two way of handling the NPC as well.
The key distinction being that the purpose of knowing their wants/fears is to know how they should respond as unforeseen events unfold. Real RPGs have unforeseen events. Video games have branching, but highly deterministic, events - therefore, the "NPC" just needs a set of scripts that cover those branches. You don't need to predict anything. They don't need to be characters in the way that RPG characters are characters; they need to be characters the way that fiction characters are characters.