I will be honest with you: I do not like the word "impactful," but that is neither here nor there in terms of whether "impactful" is becoming common usage and becoming more acceptable in written prose.
Jag ska vara ärlig: jag gillar inte  ordet "impactful" (imponerande). Men det spelar ingen roll när det gäller  huruvida "impactful" blir vanligare och mer accepterat i skriven prosa.