So, I wanna talk about how
utterly weird Monster Hunter World's official configuration for the Steam Controller is. Typically, official configurations for Steam Controller games come in two types: bindings, and native support.
Bindings are where you assign a specific keyboard, mouse, or Xbox input to the Steam Controller. Such as say making the right trigger the left click on your mouse button, or assigning WASD to the stick, or say like the "Q" and "E" keys to the face buttons. These are the most common types of official configurations for the Steam Controller.
On the other hand, you also have official configurations with native support. What this means is, is instead of getting a configuration where you might bind the specific buttons or keys to the controller, you instead bind actions to it. For example, you'd assign "Fire Gun" to the right trigger or "Reload" to the X button. These typically allow for a lot more customization compared to what you could do alone, and usually allow you to designate different actions for different parts of gameplay (I.E. menus having one set of control, or vehicles having their own controls)
Monster Hunter World is actually a game with native support. You can tell because it gives you a list of actions by default with the official configuration, and there's an option to switch to "Legacy Keys" in there. But they've done something rather unusual for this native support. All the "actions" are just named after generic buttons on a controller, such "Face Button Up" and "Face Button Down", in addiction to having a special action for hitting both attack buttons at once with a single press. Likewise, it seems to allow for two different sets of controls, one for melee and one for aiming. It's very peculiar, and I've never seen anything like it before in the nearly three years I've owned the Steam Controller. There's just one problem...
... none of these "actions" appear to work as far as I can tell.
To top it all off, even though this configuration is official (it was there before the game launched, and is always atop the community), it's not in the "Recommended" section like an official configuration would be.
Given the way Steam Input works, and based upon how these buttons are named and the fact that Steam Input supports the Dualshock 4, I suspect this was going to be how you were suppose to get Playstation prompts in game. Unfortunately, unless someone finds said prompts in the game file there's no way to verify it, because the configuration doesn't work and was only ever finished for the Steam Controller itself. No configuration exists for the Dualshock 4 if it's plugged in, although you can adapt the official configuration from the Steam Controller over just fine if you want. Monster Hunter World itself works fine with an Xinput based solution, such as an Xbox controller or another controller running through Steam Input and the generic gamepad template. Really makes me wonder what was going on with this config tho...
TLDR: They made a native Steam Controller config to do what the generic bindings can already do. Except said native config doesn't work anyhow.