Warriors
Rather than using up all their draft capital for the next several years PLUS all their youth putting everything on one Lauri trade with no way to get out if it goes south, Warriors keep their draft capital to make other moves at the deadline if necessary
Warriors get additional draft capital back
Get win-now pieces with a center who can stretch the floor and defend the rim
Get a true replacement for Klay with a 3-level scoring SG who can hit from outside, and a 3&D rotational wing
Keep Kuminga who can anchor your perimeter defense
If Zach doesn't work, if Draymond gets in trouble again, if someone else comes available that they really want, or if everything works perfectly and they'd rather have excess draft capital to move up in the draft for a player they really like, all these scenarios can be addressed by making this trade. With Lauri, you better have a crystal ball guaranteeing it works and everything is perfect because his expiring $18M won't be enough to make real changes if it goes haywire...
Wizards
As a team that's in a rebuilding stage, get an influx of young, real talent that can be a part of a young core today - send out picks that will be a gamble for youth that's already proven
Bulls
Get 2nds back for taking on the second-worst contract, helping the Wizards pay for their new pieces and giving up some youth
Get back some expiring contracts that may be flippable at the deadline