The US government classified the Power Mac G4 as a super-computer due to its computing power surpassing 1 GIGAFLOP.
In 1979, a GIGAFLOP was seen as powerful and scary, but now we carry thousands of GIGAFLOPs in our pockets with modern devices.
The marketing genius of Apple used the munition classification of the G4 to promote it as a 'Personal Supercomputer', leveraging the restrictions to market the product.