When I am setting up a document for signing, rather than sending to myself via email to sign it, it would be easier to be able to sign it whilst I'm setting the document up. This is especially beneficial if I need to add a line of text somewhere in a template (an addendum) rather than waiting until I email it out first. Where an addendum is required, we need that in place before it goes to the first party which must be me to be able to add the addendum but usually, I want to be the last person to sign it once I've verified the signatures of others.