Since the Constitution is silent on what qualifies as an “official signature”, a Court would likely consider what is deemed an “official signature” generally. Electronic signature is considered official in corporate governance, financial transactions, legal proceedings, and even legislative action.
There is no reason to think it would be ruled unofficial exclusively for the purpose of executive authority ... and thus it would be a Presidential signature for the purpose of Constitutionality.
SnakeDoc
I understand your position, but the POTUS is unique in our country in that he has the final say on whether legislation becomes the law of the land. The act of signing any contract verifies that the signer understands all the ramifications of the contract and accepts and approves of all that the contract encompass.
The POTUS is held to a much higher standard than a bank employee or a law firm partner. To say he should be treated the same greatly injures or balance of powers supposedly laid out in our constitution.
Can 2 blinks of his eye be construed as a yes if he is semi-conscious laying in intensive care, and thus authorizing legislation to become law?