It's a "Serebii has a site to run, sleep deprivation, recovering from norovirus and things to prepare for next week and thus isn't on N-Europe constantly."
I believe I posted it before, shall do some hunting, but from memory and it was based on that service that exists. It starts off negligible, but at 4 player, it builds up to a constant stream, and the processing for it could also impede the processing of the game. In most games, this would be negligible due to how games process online, with extrapolation etc. but with Fighting games which don't use that would then have their performance impacted. It'd be negligible for fast connections, but when you connect to someone far away or with a comparatively poor connection, it would impact things.
Will hunt those numbers for you.
Pic of the day. Long before the game release, we revealed new fighters with videos. The video quality of online streams is not always the best, though. Luckily, you can watch them as they were meant to be in Movies mode on the Wii U version.
You can even re-watch videos that play after you clear Classic mode and Allstar mode. This is a list of videos which are unlocked when you clear certain things. They tend to be short, but you'll get a lot of information if you play them all in one sitting.