In 10 years time, you unearth your old Bitkey setup.

Bitkey went bust after 2 years of operation. The Bitkey app is no longer compatible with current phones. You might have your keys, but you do you have a way to access them ?

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Bitkey does have its downsides (the fact that 2 of the 3 keys are hot is the main one, and it's too large of a compromise to ever make me want to use it as my main wallet), but I can't see how vendor lock-in is one of them. You can send out all of your balance to any other wallet at any time, so you're not really locked there.