From the article I linked, "Though downloadable content (DLC) will remain a constant fixture for ”Street Fighter V," Capcom has promised that the first disc of the game will be the only disc.". Which contradicts this new Arcade Edition release.
Or... this is a poor turn of phrase on the part of the article writer. A click through to the source reveals the original quote:
"
This is the only disc you're ever going to need to own to get all of the content in the game, but we'll be revealing details of how our post-launch content happens at a later date, but it will be good news,"
So! If you own an SF5 disc
it will indeed continue to be the only disc you'll need thanks to a free update, but newcomers, tournament organizers wanting to download less stuff or those looking for a shortcut will be able to pick up a disc of the new edition.
Is this so hard to comprehend?
Please read.