Has anyone set up anything like this before?
They allow you to provide a third party with all the details they need to access your passwords. It's therefore highly recommended to keep these kits at a safe location only trusted parties can access in case of an emergency.
You can also opt to keep your master password in a separate location or with a separate party, which precludes a single party from gaining access outright.
One could even envision combining it with something like Google's Inactive Account Manager (https://support.google.com/accounts/answer/3036546?hl=en ) to implement a dead man's switch by having an email sent on your behalf after a set period of inactivity.
I wouldn't want to trust them with my master password in plain text, though, which would defeat the purpose.
https://support.google.com/accounts/answer/3036546?hl=en
It allows you to setup access to your account if you've been in active for a while, presumably that could eventually happens ... sometime after you die.
I started setting it up but when faced with writing an email that probably only gets sent when I'm dead to my wife / kids ... I kinda didn't want to keep going.
There is also a delete option.
No third party to deal with.