For those interested in the digital version of ARMS, it was revealed to be around 2.2 GB in size,
For some comparisons to recent stuff on the Switch, the game is around 200MB bigger than a save file of Minecraft for the console and around 5.2 GB smaller than NBA Playgrounds. Even in terms of fighting games, its around 500MB smaller than Ultra Street Fighter II.
https://www.destructoid.com/arms-onl...s-437784.phtml