As camera systems get smaller one design issue could be the smaller batteries that leave us with short run times. This is especially true with many of Sony's mirrorless camera systems. If you're looking for longer run times, IndiPro Tools has a number of different Battery and Power solutions available as seen in this interview during the NAB 2016 show.
One important design difference with the IndiPro Tools cables they point out is having DC converters placed outside of the dummy battery. Not only does this reduce any possible heat from generating inside the camera (problem for some Sony cameras), but they also say it prevents any digital noise (a.k.a RF, EMI, etc.) that could affect your recorded footage.