For a few reasons, I have to say 'no'. I mean, I think it's a very interesting and entertaining game, but I feel that the things that make it creepy or scary lose their edge quickly enough.
I myself do not find animatronics or puppets scary. I don't find many things approaching the uncanny valley to be off-putting or scary anyway. That said, the only animatronics from FNaF that I find scary are Old Bonnie, Old Chica, and the Marionette. All from FNaF 2. I find them scary because I think they have scarier designs than all the others. (Old Bonnie's missing face plate, Old Chica's numerous teeth layers, and the Marionette's face, plain and simple)
I disagree with the people who say these games don't have atmosphere. I think the fixed, isolated position you take, with the slow, gradual checking of the cameras of an after-dark hours building with, imo, subtle sound design, has pretty good creepy atmosphere, but, like the animatronics, what makes it creepy does wear off after a while.
I actually think the creepiest part of the games are the Commodore 64-style minigames after you die in FNaF 2. They engage you in a new gameplay style without warning and very little instruction, and you have to figure out what's going on in a very short amount of time, perhaps even replaying it to get a better sense of what the child-killer was doing.
Like others, I think the games are more enjoyable when exploring its lore, which is decently obscure, making interpretation a fun part of the game. Gameplay does boil down to a very certain pattern, with the cameras being all but superficial if not for the fact they have to be activated to stall Foxy or the Marionette. I've heard it said once that by continuing to play the game, you yourself become more robotic, as you stop checking cameras at random and closing the doors at the slightest noise. You get pulled into a routine, all for the sake of keeping yourself alive. Not that this always makes for engaging gameplay, but I actually thought whoever said that had a good point.
So, yeah, with that all out of the way, no, I don't think the games hold onto whatever makes them creepy for very long, but I do think they are entertaining games. Besides, I think the games come at good prices, and I'm someone who's less irked by a few disappointing features if I didn't pay very much for it.