I don't know as much about Kendo as I'd like, but I've studied Chinese saber and straight sword, both of which include disemboweling techniques.
In the case of wudang fencing, techniques which require penetration are not utilized (for obvious reasons;) but saber methods I know do not require penetration to exhibit, just continuous blade-to-body contact, because you can press the curved blade into the body with the off hand. However, you don't have a highly developed wushu saber sparring sport like Kendo.
Thus I'm wondering if Kendo discards these techniques to focus on clean hits in the competition sport, or if they have a place in the sport and practice.
Information on the practice and techniques in kenjutsu also welcome for historical perspective. My understanding is that such techniques were utilized in the past.