Semantics. QKD is a way of obtaining a secure key which we then use to perform one-time pad encryption. In other words, we use it for encrypting information.
I don't understand this. Sending a one-time pad key is equivalent to sending the plaintext, as far as information transfer goes. (Otherwise, it isn't a real one-time pad.) The only advantage of the 1TP is that we can send the pad when we can get a secure communications channel, and then send messages at arbitrary times over insecure channels. If you have a reliable and persistent secure channel, why bother with the 1TP key?
Excellent question! QKD is just what it means, key distribution. There is actually no transmission between sender and receiver, instead it randomly establishes a secret, shared key at Alice's and Bob's place. Therefore, to do transmission, you use OTP to perform encryption.