I wouldn't be too comfy with b) either, as it sounds like a complete unicorn. At best, it's hard to know the "quality" of that backing and even then there are ethical and legal liabilities.
Serious question? The principle is called "opportunity cost". Chilling out and touching grass is free - but you could also have spent that time working, producing stuff, learning or whatever. You have "lost out" on a potential benefit due to exactly how that time was spent.
With phones, like with other things, a bit of protective covering goes a long way.