I usually agree with Yahtzee's views, sometimes it's more of a hit and miss, but this is one of the few times when I completely disagree.
I mean, I get the jumpscare hate. I dislike them too. It *is* the cheapest sort of horror. Yet I heavily disagree that FNAF is simply a glorified screamer. Yes, the game does contain jumpscares. Yes, they are an integral part of the game. But they are just a part of why (in my opinion) the game does 'horror' very, very right.
There are two fronts where I personally think FNAF succeeds very well. The first one is that it is one of the most perfect renditions of what it feels to actually be in a nightmare that I have ever seen. Whoever had a truly scary nightmare can easily identify all the elements - atmosphere full of dread, an immediate, usually hidden yet absolutely horrifying danger, and - most importantly - helplessness. In a nightmare stuff isn't logical, isn't rational. There is no rhyme or reason, no backstory, the rules aren't clear. You are at the same time perfectly aware of the situation and still hopelessly confused. This is btw also the reason why I heavily dislike arguments like "why can't I have a weapon", "why can't I roam around" or "why is the power needed to keep the doors open, instead of the other way around". The answer is simple - nightmares have their own internal logic. They can't be dissected, or rationalized. They are what they are, and this is what makes them scary. When you know too much about something, or can explain it logically, it stops being scary. Why does the guy keep returning? Who cares? He just does, and you need to accept it. There's no reasoning with a nightmare.
Second thing I think FNAF does right is how it manages to make the entire experience cerebral and immersive, and this is EXACTLY because of the dreaded jumpscare. Character actually stuck in a horrific situation will a) be scared, b) paralyzed by anticipation of what might happen to him, be it fear, pain or death and c) probably do everything in his power to avoid an undesirable fate. And this is extremely similar to what player goes through while playing FNAF - the scary atmosphere immediately provides the elements of fear, and the jumpscare is the undesirable fate which both provides the anticipation part AND the motivation to find ways to avoid it. Again, this is also why the game isn't merely a glorified jumpscare - horror which relies exclusively on jumpscares doesn't give you tools to avoid it, doesn't provide the motivation to actively search for ways to nullify it. It's just there to appear suddenly and yell BOO!! But in FNAF, you know there is a method to avoid it completely, to play the game and NOT get scared... which, again, is the parallel of actually living through a horrific situation and surviving. And not just surviving, but surviving as a result of your own actions. I honestly can think of very few computer games which manage to succeed in this so well. In your regular AAA horror games you actually strive to find the next scary thing, you relish it, but in FNAF you are doing everything you can to avoid seeing it. Which one is more true to actual horror, what do you think?
If I have to pick an actual flaw of the game, it is that is somehow got too big. Too popular. Everything that scrounges such internet fame will eventually become insufferable, be it because of the overenthusiastic fanbase, or the inevitable hatred which always accompanies something popular. I love FNAF for what it is and for what it does, but I dislike almost everything that accompanies it outside of it, be it endless Let's Play videos in which people try to outdo themselves in making silly faces while pretending to be scared, lore nuts who start dissecting every pixel for hidden meaning or haters who start foaming at the mouth at the very sight of a brown bear's head. I love that FNAF's author managed to make money out of it, but part of me truly wishes if this stayed a niche title, an underground hit which noone would be aware it even existed except for a few lucky people who managed to stumble upon it and subsequently appreciate it just for what it is.