The biggest issue here is failing to relate to your intended audience. (IMHO) The type of people that lose their secret keys are the type that don't know to ba

The biggest issue here is failing to relate to your intended audience. (IMHO) The type of people that lose their secret keys are the type that don't know to back them up in the first place. They would never know to look for a service like this, and if they did, they would at that point also likely understand the value of their private key, and come up with a means to keep it. The biggest problem with this whole project is the fact that people need to trust you with total control of their money. That's a big ask .. and that you're asking them to trust their money to your coding skills, that you're going to pile lots of private keys in one place (making you a target), and crossing your fingers you don't run across persons smarter than yourself. If you get even a few people to use this service, it's going to end perilously.