Though choice is still important, why that gamepad? Especially if it was the wireless version.
Building the controls with wired arcade buttons and an arcade joystick would be a little pricier but you'd get parts designed to take a beating, plenty of real world usage to demonstrate this and no potentially flaky usb/wireless stack that you have no control over to deal with.
I could take some guesses. It's cramped with a lot of people; wires invite tangles or damage if someone accidentally yanks on it. Especially if you want to operate the vehicle from both sides of the interior.
Those controllers have millions of hours of playtesting by people that are sensitive to the slightest twitch. I'd trust them more than most automotive components.
I'm more curious to know how they run the control lines. A thruhull at 400 atmospheres must be something special. Or maybe it's wireless to the machinery outside? But the carbon fibre and titanium enclosure would be a problem.
I would not actually trust them more than an automotive component, I think most accelerator pedals use Hall Effect sensors (usually two of them in the good designs) that are much less likely to wear out and cause spurious inputs or failure than the basic potentiometers on a game console, especially a very cheap one. Get an X-box controller at least, and have a couple spares wired in, in case the wireless one fails.
Building the controls with wired arcade buttons and an arcade joystick would be a little pricier but you'd get parts designed to take a beating, plenty of real world usage to demonstrate this and no potentially flaky usb/wireless stack that you have no control over to deal with.