5A is the max rating for USB-C. What you’re looking at is probably a 5A cable with a “10A” molded into the connector in true sketchy knockoff fashion.
To answer OP, USB-C connectors are often used outside of phones/tablets like with hobby electronics like boards to control LED strips that could benefit from more current. Unless this cable is super thick, there’s little chance it can actually handle 10A and even if it can, the connectors aren’t rated for that much current.
Your middle seat passenger doesn’t seem to mind so much.