Wow I didn't believe this at first, so I dug more. AWIS requires the root key of an AWS account. I found a forum that does suggest creating a new account solely for AWIS.
https://forums.aws.amazon.com/thread.jspa?threadID=126537
Still I'm surprised they would suggest sending the root key to your account over http. Even if it is just the id and not secret it still seems like something you want to keep secure. I don't use my root key for services. I create new accounts and IAM roles.