What's the point of tricking someone "it was all their idea" , if they get the credit, and with it, the promotion ? Sure the work will get done better, but it'

What's the point of tricking someone "it was all their idea" , if they get the credit, and with it, the promotion ? Sure the work will get done better, but it's not like we're saving lives or doing something important, so what's in it for me ?