Excuse my silly question, but what's the point of pre-buying a game, if it will only exists as a downloadable copy. I get you want to gift it for xmas, but for the rest of players? The point of pre-sale is to make sure you will get one when it comes out?

I personally agree that pre-buying is silly in today's world of digital distribution. But I will point out that most pre-sales now come with a digital item or two or five that's exclusive to pre-orders. Additionally, if you pre-order, you can sometimes download the game a day or so ahead of time, and then have it "unlock" when it's released, allowing you to play at minute 1. I'd wager GTA VI is well over 100 GBs, so this is actually a reasonable benefit, especially considering the potential for CDN crashes at launch time.

One reason for doing it is that download servers will be absolutely slammed on release. A pre-order will often times come with the bulk of the download happening a few days in advance, and then a very small download at release that contains a small amount of data that makes the game playable. This is an argument for buying a week out, not 5 months out though.

Another is that there are very often below-RRP deals for games in advance, but if you buy it on launch day you'll be paying RRP.

Generally it doesn't make sense, but in this particular case the servers are going ti be so overloaded with people trying to download it that it might be worth it to preloaded the game. Now of course they're probably going to have separate author servers that will probably also be overloaded with everyone trying to login at once (why does a single player game need you to log in first? good question!) so imo you're probably going to be screwed either way

Usually, they throw in some free content or dlc for pre-purchasing, entice people before potentially negative reviews.

The benefit for the player is they get a few additional in-game cosmetic unlocks, and the benefit for the publisher is they get a large wad of cash in advance and and an excuse to generate a new hype cycle surrounding the game.

In addition to what the sibling comment wrote, many platforms will let you download the game in advance, and "unlock" immediately at launch. Some people want to be among the first to play, I guess.

It's for those people that can't wait a second after release. As if the game is any worse if you start playing it a few days later.

There is speculation that the size on disk will be over 200Gb, so one advantage is preloading that.