I've never had a package stolen off my front porch, but if I reported to Amazon that a package that their tracking system reported delivered was not actually delivered, what would they do? I'm guessing they'd just reship the items. If they didn't, my Amex would reimburse the charge under their theft protection. If I'm not out any money for stolen packages, their indoor delivery system is protecting their interests, not mine. So I'd want to know how much Amazon was offering to pay me to install and use this system.
(No, I probably wouldn't use their system regardless. I already have remote access cameras and door lock/unlock systems, and no one but me and my wife can use them, which is how I like it. But my point is that this is just another of many situations where I'm being asked to insure somebody else's interest. If someone wants me to insure their interests, they need to pay me to do so, not the other way around.)