I heard they are great for killing billionaires in experimental deep sea rigs

They use it to control a submarine

Operating parts of multi million dollar navy ships, according to articles. Not joking

The Steam Deck and Steam controller have touchpads which make them totally usable as a mouse for normal PC usage like web browsing

Disneyland uses Steam Decks to remote control droids in Star Wars land.

They can be quite useful in hobbyist robotics

Actually yes.

I worked on a crew building pole barns in Colorado. For anyone unaware you basically dig a bunch of holes, set wooden columns in them and pour concrete around them, then hang the rest of the structure off those columns.

We had a dude that swore by the xbox 360 controller. We tried to get him to use a framing hammer to drive his nails but he would only use that 360 controller.

We also did a lot of acid. If you see a weird barn in Colorado, look for the microsoft logo pressed into the wood next to the siding nails.

They are the OG electric vibrators for people who can't buy vibrators.

Several modular synth modules use joysticks for control over parameters, but one of the coolest I’ve seen is one from Delptronics that uses a wii nunchuck controller to send out control voltage. Hagiwo I believe also has a similar DIY design.

In college I was on the robotics team. We used several different controllers to drive various robots. I made a little tank steering robot that was remote controlled from a PC with an Xbox 360 controller. I later rebuilt it to use a Raspberry Pi and added a pan/tilt mount for the camera controlled from the controller's D-pad. We also used a Wiimote to control our competition robot, using the accelerometer for steering which was pretty cool. This was in like 2010 when motion controls were still a relatively new and cool thing.

I do recall a gaming controller being used to pilot the titan submersible that is now on the ocean floor. May their souls rest in peace.

In Ghostbusters 2 they rigged up a Nintendo joystick to drive the statue of liberty through the streets of NYC. Does that count?

All a controller is is just some buttons on a wire in a portable form factor.

If you want to use it for Excel, you can.

I used one on a Raspberry Pi to drive a self build remote car wirelessly.

We had a subcontractor drive a wired camera mounted drone through the sewers with it. Some use LIDAR or SONAR instead of just cameras. Game controllers are pretty common for these.

I have one of mine configured as media controls when I'm wandering around the house (8bitdo controllers ftw)

Hacksmith on youtube uses playstation controllers for remote operation of their giant mechs.

Some guys I used to know used them to make music, as some sort of midi controller.

I think it was med students who use controllers to control flash card decks for studying.

Also as PowerPoint remotes.

I used to use a mini game controller for artwork. Like up on the dpad would zoom in the canvas. I had buttons for undo, redo, switch to eraser, rotate the canvas, flip it, etc.

I am working on getting my XBox controller to work with a Raspberry Pi/Astroberry setup to control my telescope.

Scrolling around LibreELEC to get to my gaming folder

I would also add VR controllers to the list and I had used them for painting.

We used a ps4 controller as a mouse on our tv/media center. Its wired/Bluetooth and comes in as a mouse on our Linux box. No setup, just connect and it works.

Fire up halo 1

Get in the gunner seat of warthog

Tape right trigger down

Profit

On a very old computer of mine, the "y" key was completely missing and I couldn't replace it because the contacts were broken so I just use JoytoKey and a USB SNES controller.

I've also used a similar setup for navigating some image boorus but, for obvious reasons, I wont specify anything further.

I've seen some people on YouTube use them to control their CNC.

playstation and Xbox controllers make good Kodi/XBMC remotes for a laptop connected to a TV.

Some digital artists use Switch JoyCons for shortcuts in Clip Studio and other painting programs.

Haven't actually done it yet but I'm going to buy myself a Teensy for my birthday next month, set up headless M8 on it and control it through my Steamdeck.

I use my flight sim gear as a fidget toy, hope that counts.

Typing with Donkey Kong Bongos

Iirc (on the phone now,) cameractrls allows panning and zooming with a gamepad.