It's for those who don't feel secure about their computers (travelers, paranoiacs...) or need to be 100% sure nobody can read their messages.
So all of them would have to trust and buy your device that is ''100%'' safe?
It's much easier to use some open source software that would do the same thing than to buy some device that can have backdoors, hidden code and can be affected by supply chain attacks.
so you prefer using an open source soft wallet over a hard wallet?
any memory in the device could be erased pushing a button, you could also erase all memories but your key