German charts are based on revenue and not actual sales i think. So if u buy a CD single (if that still exist) it will count more than buying the track on iTunes. One stream is ''worth'' one cent, I don't know if they will go by the formula one person one stream or one person streaming the same song for a week and them counting those streams.
I think every country should have a digital chart AND a popularity chart.
There's no question that streaming is increasingly becoming a huge factor and it can't be ignored. But having a pure sales chart is also important. Many people who follow UK charts are extremely against converting to a Hot 100 type formula. But in reality we need both in this era.