you store ur photos on fb same way you store your money at the bank and your code on github, its delegation of concerns, you can make same argument for literally anything....not using your own silicon, growing your own food, financing your own venture, owning your own land, etc etc.... maybe its more "secure" vs "less efficient" or some other tradeoff. and you have to get the right balance or take risks for optimal efficiency / profit/whatever your values are