The boxed copy contains a code, not a disc
What the retail format means for downloading and account ownership.

Rockstar's current versions FAQ explicitly says the boxed version of GTA VI contains a digital download code and no disc. “Physical” here describes the packaging and retail sale; it does not establish an optical copy of the game.
A box does not replace the download
You still need to redeem the code and download the game on the appropriate platform account. The box is therefore not a way around the storage requirement or a slow connection. Plan around the published installation requirement of up to 212 GB and the date on which the retailer will actually deliver your code.
Rockstar expects boxed copies to ship or become available for pickup from 12 November. The digital pre-load window opens on 10 November. Those two dates describe different events: if your retail code arrives on the 12th, you cannot use it on the 10th. Neither event is early access to the game, which is scheduled for the 19th.
Buy for the account that will redeem it
Rockstar distinguishes platform and regional code rules. For PlayStation, match the code's supported region to the account that will redeem it. Its FAQ groups eligible countries by redemption region. For Xbox, the same FAQ says the codes are not region-locked. That statement should not be widened into a guarantee that every retailer accepts every payment method or that all commercial terms are identical.
A code is redeemed to an account. Do not treat an unopened-looking box, a retailer's generic disc icon or the ability to pass the packaging to someone else as proof that the entitlement can be transferred after redemption. Check the actual product listing and platform terms before paying.
Ultimate is a separate upgrade
There is no announced boxed Ultimate Edition in this FAQ. A boxed Standard buyer can purchase the digital Ultimate upgrade after redeeming the Standard code. Keep the base-game code and the add-on distinct when comparing offers; a cheaper add-on is not a copy of the game.