What will make Captchas valuable in the future is their ability to act as signatures, verifying you, the owner of the account, were physically present when you

What will make Captchas valuable in the future is their ability to act as signatures, verifying you, the owner of the account, were physically present when you did whatever action required verification. They will not just be roadblocks, but checkpoints verifying not just that you are human, but that you are the person you claim to be.