Serial I/O is common Hello World example for Raspberry Pi. I think you have to worry about less things than adhoc wifi networks.
> likely much slower
It's slower, but not much slower. The baud rate can be set up to 4,000,000, where a megabyte would transfer in 2 seconds. These "gifs" don't seem to be more than 10 seconds long, so they should be less than 1 MB, judging from random Giphy mp4s.