The Wii kept survival horror flourishing even as the Playstation 3 and XBOX 360 let the medium fall by the wayside. Titles like Silent Hill: Shattered Memories, Fatal Frame and Obscure: The Aftermath can be found very cheap these days if you still have the system.
Motion Controls are Immersive, And Spooky
The Wii was the only system with "point and shoot" Resident Evil 4, where it was possible to use the Wii-remote to aim. Even the recent Switch release doesn't have that. And there's something much more immersive in using motion controls in horror games because it forces the player to engage physically; there's a reason Arcades have plastic guns to point at the screen. The most the Playstation 4 does these days is rumble, while the Switch contains two joycons that can be used as separate controllers or an entirely new way to play with motion tracking. The Switch followed its predecessors like the Wii and the Wii U, trying to engage their audiences through motion.
Motion Controls Sometimes Suck
Unfortunately, many games on the Wii tried and failed to incorporate its motion controls-- it's one thing to be searching every nook and cranny of a dark house for a hidden item, but quite another to hold your arm out and slowly, meticulously light up every corner of the room with a flashlight. Fatal Frame IV was criticized for this, as Kotaku reported "you're fighting the controls as much as the ghosts."
However, when done right and in the proper atmosphere, using motion controls can completely revamp an experience. Developers haven't given up on motion controls these days; they've simply moved to VR.
The Wii is still worth playing due to its sleeper hits, which were supported even when other developers preferred to play it safe. After the Wii, it took quite a few years to reintroduce motion controls in the form of the Wii U, and finally the Switch. PlayStation tried dabbling with its own motion controller, but the PlayStation Move wasn't supported by many games. People continue to play their Wii to this day for its easy accessibility, but it didn't do a great job pulling in hardcore gamers.
The Games Were Varied
The Wii still has a ton of great titles available to buy for those who have the system (or the Wii U, which takes Wii games!) Silent Hill: Shattered Memories put players in the role of a man trying to find his daughter and running from grotesque abominations, Fatal Frame IV allowed players to use the Wii remote as a camera and Obscure: The Aftermath was a blend of coop and survival horror that acted as a slasher film. The Wii even featured niche Japanese horror such as Ju-on: The Grudge, which acted as a Haunted House Simulator where players could use the Wii remote as a flashlight to explore the environments. It wasn't rated highly at all, with a 2.5 score on IGN, but this was the risk taken on experimental horror-- throwing games at the wall and seeing what stuck was what the Wii was good at.
Shattered Memories was an extremely divisive title as well. While Silent Hill is a cult classic, Shattered Memories rewrote the story and placed players in the role of Harry Mason who goes to Silent Hill after a therapy session to find his seven year old daughter, Cheryl. There are monsters in the game, but they're invincible as Harry has no weapons to use.
The game took risks in its storytelling and delivered a great ending that was based on the choices players made during the title. The horror aspect worked for some and fell flat for others. On the one hand, it is impossible to fight back in Silent Hill: Shattered Memories, and that can bring with it some tense moments. On the other hand, players are entirely out of danger for a great portion of the title-- only when Harry is the "Nightmare world" is he forced to run. Regardless, it's a great entry for those who still have the means to play it.
The Concept of Risk
The Wii's gimmick often proved to be a double-edged sword. Getting motion controls wrong in a title meant rendering that title unplayable, even if the rest of the game was great. The ported The World Ends With You for the Switch messed up motion controls and reviewers warned not to play it docked, but for those playing in handheld, the question becomes, "why not just play it on Google Play for half the cost?" The same argument applied for the Wii- either motion controls were great, or people preferred to play it on a more powerful system like the PlayStation 3.
Horror games on the Wii only worked when the motion controls worked, the atmosphere was just right and it wasn't better elsewhere. Classics like Resident Evil 4 showed that motion controls could enhance a game, and as Triple AAA publishers moved away from anything that wasn't a guaranteed moneymaker, the Wii continued to take those risks. The Wii U carried on the torch by having two screens, and eventually the Switch hit a home run by creating a portable hybrid. Survival Horror found its niche and survived on the Wii, and most of those titles are still available today for that reason.