Tbh, out and out fastbowlers in T20s have to be used very shrewdly, otherwise they tend to be extremely expensive - given how short the boundaries are and how an edge off their bowling can go for 6. This doesn't matter in Tests as the sole objective is to get wickets, stemming runs is usually a secondary concern.
Players like de Lange, Pattinson, Tait etc are like heavy artillery, they have to be deployed with caution as they are just as likely to cause collateral damage as they are to do the opposition harm. In T20, a seamer who is accurate and can vary their pace well is like gold dust - hence why Malinga is such a valuable commodity.
KKR doesn't have this commodity really - they just have out and out pacers or mediocre trundlers/cannon fodder.