Obviously depriving your child of the internet and computers would be doing them a huge disservice but I do think there's something about emotional and interpersonal development that are being severely harmed.
This is really unlike anything we've seen before so we don't know what the effects are going to be. Television comes close but even then, it was pretty easy for parents to regulate it since it wasn't portable. You watched TV when you were at home, period. And you only watched what was on at that time.
With smartphones, you can be engaged all your waking hours and there's a billion things to be into. The gain in knowledge is impressive, but there's also a cost there.