What exactly is the Play online button?

[Super Vegeta]

When i press it shows a save with my gamejolt and a preschooler
what is it exactly because i don't see anyone walking around or is it like lan or something?

 

[DevoidLight]

Online files are protected from hacking and mods, and let you level up your character.

 

[Darkfire]

it is a save that is saved online
it is the only way to use the GTS or the Friend Hub
it will also be the place where competitive play will be supported
the "offline" saves will be basically a sandbox mode where you can run mods mess with scripts change your save file, etc
there will be online support eventually there but it wont be as extensive