Good horror will utilize both. Dead Space was about as scary as a week old kitten because it only had one move. Out of the entire game I can only think of one moment which actually scared me; the Invulnerable Necromorph hunting throughout one level. Though on one of the later levels you could hear a weird cult-like chanting noise, which was creepy.
Whereas Silent Hill 2 built up an effective atmosphere using its soundtrack and unsettling imagery; only sparingly using jump scares. And I guarantee they got me, every single time. Because the jump scares were uncommon, there were moments when I was absolutely terrified that something was going to jump out on me, even if it never actually occurred; the Historical Society section being a prime example.
Compare the two games, and you'll see that the scares in Dead Space are mostly cheap and ineffective, whereas Silent Hill 2 consistently hits.