I'm not an expert here, but yes, there are a lot of incidents and accidents that need to be investigated that don't involve the ship sinking (remember the Ever

I'm not an expert here, but yes, there are a lot of incidents and accidents that need to be investigated that don't involve the ship sinking (remember the Ever Given?). Plus, having a device installed in some kind of floating pod which detaches automatically when the ship sinks requires a lot of extra equipment, it has to be on the outside, so exposed to salt water and corrosion, etc.