I’ve seen a video of US Navy using an Xbox controller (arguably for experimental weapon iirc but still). If it just works why overengineer it? I would be more concerned about that hull (scuttlebutt says it was just carbon over titanium frame, not titanium hull overlayed with carbon). However I guess we will have to wait until they find the boat to know the reason for failure.
Exactly. Making the controls yourself isn't necessarily better, as long as the rudders and engines are engineered properly. Some seperate (emergency) control might be a good idea, in case the Bluetooth fails. Just to get the submarine back to the surface.
The submarine is a one-off experimental one that isn't certified, hasn't been used a lot and dives deeper than almost any other submarine. That's enough alarm bells for me. Whatever they use to control the vessel is irrelevant to me.