I wouldn’t consider it a waste. Navigraph data is way more accurate and complete than the stock sim data. And it gets updated on time, every time, not days or weeks later.
Personally, I consider the charts essential. I wouldn’t even think of flying without them, particularly in the planes where they’re still integrated into the GPS.
I’m anxiously awaiting for Navigraph to release the mod that adds that chart integration back into MSFS actually. Despite having Navigraph running on a touch screen or tablet, I still like having it in my GPS as well.