Added for the first time with Borderlands 4, this activity almost entirely lifts the whole idea of a Destiny Nightfall, tasking the player to tackle a weekly rotating mission with a set of pre-determined modifiers to scale up the difficulty, forcing you to adjust your build and try out new things.

The only problem with this however is that in Destiny, a Nightfall is typically (and in fact, almost always) a harder version of a strike (a new piece of content you won't find elsewhere in the game), which is what makes jumping in to it for the first time so fun.
In addition to this, you'll often find exclusive loot in these activities you can't typically obtain elsewhere. It's a great incentive that really makes logging on each week with some friends worth it, especially given the difficulty ramp of the missions thrown at you.
This is where Borderlands 4 differs however, with these so called Wildcards instead just being replayable story or side quests from the game. If I'm not making myself clear enough already- it's not new content. It's stuff you've already played, only with some preset modifiers, and a dedicated loot drop reward upon completion
Of course, none of the loot provided for completing these missions are unique in the sense of them being exclusive, which really does leave one giant question for the player... Why would you ever want to do these?