While your points are valid, they are not relevant in a legal sense (at least in the United States).

An electronic signature is as good as a paper signature under the ESign Act of 2000 if they follow this definition:

`electronic sound, symbol, or process attached to or logically associated with a record and executed or adopted by a person with the intent to sign the record.`

Hell, even sending the words "I accept" via Morse code over telegraph was considered a legal signature in the 19th century.

However, if there a dispute over the authenticity of the signature and found to be fraudulant, the courts have ruled that it's not a signature then.