If I buy the farm in a far-off field, I don't give a rat's pointy little tail whether or not SecDef signs the condolence letter to my family himself, or has a machine do it. It doesn't matter, to me, or to my children (also in uniform). A piece of paper doesn't make up for the loss, regardless of who signs it.
In the military, we use whatever means are available to perform the required task at minimum cost to life, blood, and treasure. Period.
/john