Because it is easier for me and the transfer speed is optimal
So you access the naze through the pi.?
And can use flight program cleanflight or betaflight. Because if not,you need to put the pi in a uart(oven) so you can access cleanflight through the usb.
It's crude but you could run an fcb off the balance plug of a lipo but you would need a dedicated socket to plug in every battery. NOT ADVISED though. Without a multimeter & knowledge you may use the 7.4v next to it. If you use a 4S Lipo you can inadvertently put 11.v into a 5v circuit.