Games don't go gold exactly a day before going live.
There is a cutoff point for when they need to start printing a master disk that they'll use to press retail copies; in this time they can still update the game and the way UE4's filesystem works, even small changes will introduces patches that are GB's in size.
Arcade Edition physical is literally the vanilla SFV disc but with a voucher. You put the disc in it installs regular SFV which is a little over 19GB. Then you install around a 13GB patch (this is what it was first me since I got it pre-Blanka) and then the file size on your hard drive is 20GBG, meaning around 13GB of the physical discs data is outright removed and replaced with a patch, so if you get physical you only save about 7GB digital install time from just buying it digital. Then you install the story mode on top of that for around another 8GB.
It has nothing to do with a master disc or when a game goes gold, I believe what michaelius is talking about is why wasn't the disc version the day 1 version of arcade edition (that was already out for awhile before the physical version) with arcade mode and story already installable from the disc for convenience with patches being for the Sakura update and beyond. Which is a very valid issue if someone wasn't following this game religiously. I mean SFV Arcade Edition, as far as I know, is the first fighting game physical re-release/DLC bundle edition that didn't do exactly this, even when they continued getting update post re-release. So if someone just saw it on a store shelf without thinking to look it up real quick, I mean they would obviously think it was a proper bundle edition based on, you know, every other fighting game re-release ever, including Capcom's own SFIV Arcade Edition.
Hell ignoring fighting games, Capcom's recent Resident Evil 7 Gold Edition did this, everything was there but Not a Hero.
Capcom could have did it this way and it would have just been like it is now, hell they could have still required you to use the voucher for the season 1 and 2 characters to enable them if having the character passes 1 and 2 already installed on the disc would cause a issue.
I'm not a mind reader but michaelius posts come off as less complaining, and more of just unhappy the physical version of SFV AE is basically pointless and the laziest fighting game physical re-release to date. I mean if I didn't get the physical version for 10$ cheaper than digital I would have went digital, as the disc version is pretty pointless otherwise. Actually the physical version has to do a title update every time you load up the game, I'm not sure if the digital version is like this, but if isn't, in hindsight I would have just spent the extra 10$.