The idea of eliminating a pressed together surface makes sense, however, frame manufacturers have a pretty large tolerance with what is acceptable bore diameter and chamfer angle accuracy. I have yet to see a frameset where I can snugly insert the sealed bearing without some play or movement. At least with semi integrated, your assured your bearing will fit snugly in the cup, and the cup is pressed in place.
Semi integrated = pressed cup & tight tolerance well fit sealed bearing. Integrated = poor tolerance sloppy ass bearing.