Kinda sorta required if you want to stream assets from storage, an approach taken by many modern games. Might not be absolutely necessary depending on your setup / game settings. BG3 also said SSD required but there’s a “Slow HDD Mode” in the settings anyway, which I believe just shifts more of the streaming burden to RAM/VRAM. If you played on a HDD without enabling it, I guess you’d expect to see inconsistent pop-in as individual assets try to stream in faster than your storage can read. But playing with it enabled might also cause performance drop if your RAM/VRAM was already close to full utilization with the setting disabled