The PDK is nothing like a "traditional H"  - it has 2 clutches and gear drive shafts each with half the gears and the computer predicts and preselects the next gear needed so power is not interrupted as one clutch disengages and the other engages.  That is what the GT3 has. It was developed a long time ago by Porsche for racing,

The single clutch sequential gearbox has become the norm in race cars. I suppose it is less  complex and lighter than PDK, but also uses computers and electromechanical actuators to do the engaging and engine management, It is unburdened by the need for gentle shifts for sure.