

Hasn’t this been a thing for a while now? Some Collectors Editions don’t include the game, because people that buy them usually want to play immediately, but those boxes might only arrive after launch. People would have to buy the game twice, so this way they can get the normal edition first and then “complete” it with the rest of the Collectors stuff.
I think Blizzard has done some stuff, where you get Battle.net credits, when you activate the Collectors Edition code, on an account that already has the digital game. This is a better system imo, but doesn’t make sense for every game. Dunno if this is only for WoW or they still do it though.
It doesn’t make sense to pre-order now, since the game is still over three months away. Prices on Steam will be the same, no matter what (until launch).
People always say not to pre-order, but I think it’s fine shortly before release, especially after reviews are out and/or you will play the game anyway. That way you get any potential bonuses or can maybe pre-load the game. Buying on Steam or GOG directly also lets you refund the game, so there is little to no risk.