w.r.t. GreenAddress: I was a user back in the day. I think Lawrence did amazing work, great engineer. I think it's a very valid choice for small to medium sized wallets, that you actually want to use. Isn't this new Bitkey thing somewhat similar in design? well not in the details but in the 'the company exists as both a security (in spending) measure and also a recovery measure'. i think it's great, but for cold storage? it's the same old same old: 'central point of failure'. you can do it, i'm not saying you're somehow "wrong", just I don't like it.