They've been using it for years and it's a terrible strategy because if the one puck carrier doesn't get it into the zone everyone else is standing still and the PK has plenty of time to get rid of it and waste even more of the powerplay. You're trying to break into the zone against 4 other players and your teammates are standing still at the blue line.
Also, there are only five teams who have a worse powerplay than the Kings. If that's "pretty successful", well I'd hate to see pretty bad. Yes I know that the entry into the zone isn't the entire reason for the powerplay issues, but wasting 30 seconds because you can't break into the zone and you have to go get the puck again certainly doesn't help. Not only that, but even when that DOES work, the other team is already set up in the zone instead of scrambling to find their positioning.