Apple can't afford bad press like that - everyone is paranoid after the Samsung Note 7 debacle...
iPhones have "blown up" before. The problem Samsung had was several units of the device started going "up in smoke." If that starts to happen with the iPhone 7 then that'll be a different story but so far this is an isolated incident. Though as I wrote this I got to thinking if Apple does start experiencing more widespread issues then that might help pinpoint the issues Samsung was having. To my knowledge their engineers have never determined the root cause - which doesn't exactly instill confidence in consumers.