Best Buy Canada has the photo showing two discs, but the specs say three discs: https://www.bestbuy.ca/en-ca/product/the-batman-steelbook-4k-ultra-hd-combo-2022/M2234341. The US specs don’t include the number of discs.
The BB steelbook apparently lacks the green disc shown in the Wal-Mart giftset photo (and presumably included in the Amazon standard version). That disc is labeled “special features.”
I just ordered from Amazon (using the link—I couldn’t find it when I searched myself) and now it’s showing as temporarily out of stock. They’ll get more, obviously.
The BB steelbook has great art but only two discs. The standard version has three, presumably 4K, BD, and BD extras.