If they’ve already decided to use a couple of well placed jumper cables, you’re past the point this is likely to be helpful. It seems the purpose of this is to avoid it getting to that point.
For me this is appealing going through airports and the like. The TSA is unlikely to jump straight to rubber hose analysis but, for a concrete real-world example, they will readily have the DEA intercept you on the way to your terminal if they suspect you’re carrying a financial instrument worth $10K+ on your person. And that’s just the US. As a US citizen traveling to China, there are plenty of use cases I could imagine for needing to move information that are only a problem once an official suspects you have something of value on the device. A concrete example that might resonate with the HN crowd: traveling between nation states with ssh credentials for your company’s infrastructure.
I can see this being useful against nation states if the goal is to avoid initial suspicion. If they’re already interested in you the game may very well already be up.