343 Industries has said it "simply wasn't practical" to ship Halo: The Master Chief Collection on two discs, following fan complaints about the game's 20GB day one download.
Halo franchise development director Frank O'Connor has said that the game was "designed to run as a single, unified product", something that switching discs would have interrupted.
"Digital is seamless obviously, but we also wanted disc users to have the same experience, without swapping discs," he wrote in a post on NeoGAF.
"Since the bulk of it [the content update] is MP or MP related, the logic is sound. There will also be a title update in there, but that in itself is a tiny fraction of the content.
"We realise that this isn't ideal for everyone, but it's the path to the smoothest eventual experience."
You will be able to play the game's single-player campaigns while the 20GB content update is installing, 343 has previously said.
The content update will also be available to download ahead of time if you pre-order and pre-download the game.
In another post, O'Connor admitted that two discs may be a solution to a different product released at a different time - but that requiring the download was the most straight-forward solution for the Collection.
"Anything is feasible, it simply wasn't practical for this product, this year in this timeline," O'Connor wrote. "The Xbox One platform continues to improve and mature, arguably faster and more meaningfully than others and maybe next year two discs or some other method would have been the right approach, but this year it's the option we have available that on balance, makes the most sense for this giant, ambitious project.
"Do I understand the inconvenience and annoyance for some users? Of course. I'm not going to blow smoke or ignore it. For some folks it will be straight up annoying and I both apologise unreservedly for the irritance, and hope that the package and the way it works more than makes up for it.
"I've been playing the whole enchilada for a week now and the ability to sample, jump from aspect to aspect, customise with skulls and playlists has been absolutely addictive and mesmerising.
"I think I would have enjoyed a box set with the same fidelity, but the way it all connects has for me at least, made it more than the sum of its parts.
"I personally have pretty lame internet and I am doing everything via Wi-Fi," he concluded, "but my installation and immediate play were all pretty buttery."