Only the people who you've added in your beneficiaries can decrypt the data if Cipherwill is hacked.
I'm sure the product has potential, and lots of effort has gone into it. I also see that criticism is hard, but if you can't be open about these basic questions then there are fundamental problems.
I should say, I'm a fan of crypto' (both types) and i'm likely your target market because currently my plans after death are not nearly as secure as i'd like!