Don't bother with the extended cut portion of the set.
The extended cut is not on a disc. Which is pretty freaking stupid, considering that the product is physical media. To get the extended cut, they give you a code to redeem it! It's not even on a disc, even though you're buying a disc! THAT is lazy and stupid, I think. I watched the extended cut, the added stuff does nothing to further the story or offer background info, character development... I wasn't expecting stuff like The Hobbit or The Lord of the Rings level of difference, but the new scenes are 20 seconds - 2 minutes long each. We're talking less than what was added to extended version of the first Hobbit movie. Not only did they drop the ball on how to access that version of the film, but I would like to add the following points:
1) the opening title where you see the name of the movie, in the movie, they slapped "extended cut" right there.
2) every time there's new footage it says "deleted scene" hardcoded in the bottom corner of the screen. So the way they handled the extended cut is very lazy and stupid.
3) not all of the deleted scenes are included in the extended cut.
In short, the extended cut is a waste. Don't go out of your way to see it, is what I mean.
Another reason why I'll wait for 5 movie set, or if there is none, get them all at once (or if all at once is cheaper). If that set doesn't include the extended cut, no big loss.
Sometimes an extended, director's, or alternate version of a film can save it from disaster, or improve on an already excellent film. Some notable examples of this include: The Lord of the Rings, Kingdom of Heaven, Once Upon a Time in America, Blade Runner (The Final Cut), and The Hobbit to name a few.
Please note, I'm not saying that The Crimes of Grindelwald is a bad movie (it's not, I liked it - I'll do a review someday soon) and I'm not telling you to not get the blu-ray or 4K version (personally I'm waiting for the boxed set and wouldn't be surprised if some are too) but rather, the way that the extended cut was handled and packaged was extremely stupid on Warner Bros.' part.
Another way to think of it, is imagine if you buy a vinyl record, and some extra content is promoted and marketed to be inside the release. Instead of putting that material onto an LP, they give you a download coupon for it...which defeats the purpose of buying the physical product to begin with. (I'm not referring to them giving you a code to download the album you also have a physical copy of)