The thing about distribution and trading is that not everyone is able to do those things. Not everyone has wifi, not everyone knows every little detail about their wifi network to input into their 3DS to make a connection, and not everyone is willing to spend money on Pokemon Bank or has parents/guardians that would let them. For some people, in-game is all they have. In-game was all I had until around 3 months ago when I found out that if I go into the network properties of my wifi connection, I can see the security key. I'd been trying to find a way to connect since the Diamond and Pearl era, and was finally able to recently. So the "this is unnecessary because you can just trade or transfer through Pokemon Bank" mentality is falsely assuming that everyone has the privilege and ability to do so.