How do you figure that? I don't know anything about how this works, but ad-hoc Wi-Fi connections are a thing, and they use good ol' TCP/IP. It just means you don't connect to some pre-existing Wi-Fi network managed by some third party (from the exchanging terminals' perspective).

1. How do you know this? 2. Even if it's the case, why would it be wrong if it's the best choice for the requirements? (incredibly simple, fast, reliable local file sharing). TCP/IP isn't the end-all be-all.

It's a peer-to-peer wireless connection that doesn't go over the internet at all. Why does it matter (and how would you even know) if they use TCP/IP?