I know a novice user who sticks with iDevices (as opposed to Android) precisely because they have a physical home button. As they describe it, "it's a magic button that's always there and always gets you back out of whatever you're in". By contrast, they dislike Android devices because of the virtual buttons that are sometimes removed in favor of more content.
Usability is very much about consistency with whatever a user is used to, and I'd be surprised if there aren't quite a few more users with similar sensibilities who find the physical button simpler to deal with.