Personally I would never use a service like this for anything that needs to be secure. That's nothing against you more my own paranoia and honestly if it was some password to decrypt my files I'd just give it in a letter to the person I trust not surprise her with an email after I die which she'd probably cry over for days.

I'd probably consider using it to just tell the people I love that I'd miss them and what impact they had on my life.

I really don't get the draw about sending passwords, life insurance policies, and other secure data when you're dead. Would my family and loved ones care about any of that if I was gone? Probably not and if the information I stored was useful to them I'd have given them a way to access it offline in the event something happened.

Not against the service I think it's a great idea just think for the non-developers out there they'd probably prefer something closer to the heart to be sent.

Note: I know you didn't really suggest people send super secret things on the site just saying it in response to what everyone else is posting.