lag in smash bros

I just got mario kart and braw but why does mario kart have no lag but braw has a ton of lag? is it just because the people playing the game have sucky internet connection? I have a really good connection 10 down/1meg up so it isn't me that's lagging. Or is it the way this game was made? maybe some people have to get better internet connection or something so it will stop lagging. I can't play a good game on braw without it then starting to lag.

Even the unexplained delay for us in PAL regions has seem to fix the problems that many Americans said they experienced so Nintendo obviously doesn't care enough to patch up the online because its obviously a problem with the Nintendo WiFi.

Ive never had problems.