Stock ignition coil cannot provide stable spark because spark occurs aren't reach to the Saturation current from Middle and high rev level. Also, in the turbo car and high pressure engine might occur lost fire phase in high rev level.

Hyper direct coil can achieve close to saturation current value because of start efficiency improve of first current.

It established the state combustion to get a stronger spark and prevents lost fire at the high rev level. With filtering effect to remove unnecessary noise, hence realized stable spark to high rev level.

It is also possible to reduce the toxic substance(CO/HC) by improving combustion efficiency.