Where do you see low bandwidth? Maybe over long distances but if I can give a pigeon a 1TiB USB stick and send it to the next city I bet it will be faster than uploading the data. If it arrives that is
People seem to always forget, that pigeons only know their way home. So you still need to get your pigeon(s) to the person sending the data with the pigeon back to you, in which case you can just pickup the data now that you're there yourself.
At that point, why waste time with the pigeons? You have to meet anyway, just make it a data exchange instead and skip the pigeons completely. That also eliminates risk of packet loss with pigeons never arriving.
In a world with safe P2P via VPN and I2P, why would you use a pigeon? Then you never have to leave your house...or perhaps more importantly, you won't need to feed potentially hundreds of carrier pigeons and clean their cages.