Possibly true. But my guess is that if you have Applecare+ and take your phone in with a cracked screen, they most likely will give you a replacement phone, not a new screen. I'd feel much better about getting a new phone, rather than fixing the screen and hoping the drop didn't cause internal damage. Plus it wouldn't void the warranty, whereas replacing the parts yourself would. Because later you might have something go wrong with the phone (non-accidental damage) and if they find out you messed with it, they don't have to cover it at all.
For you, fixing it yourself may be an option. For a lot of people (myself included), it's not. I have no desire to try to repair a phone myself.
