Its for LAN. I dont know, but according to what I have read. GBA Online has never been done sucessfully.
And honestly, kaillera does works pretty good. I mean I dont see the problem, and most got over the 56k phase. Like for SonicOlympics, there will be a ping restriction which is 110ms.
If you are part of the SEGA Master System Recorded Time Attacks, (Recorded with Gens+) you can use 56k. and then send it to one of the organizers/judges. The file will be fairly small and easy to upload, and it is not possible to cheat because Gens+ does not record in a published video format whatsoever. It has its own format that is only playable thru the emulator.
More intructions on that coming soon.