I have a WD Black HDD 4TB which transfers at 140MB/s. (versus 3000-4000 MB/s for the seagate SSD). At that rate you could move the entirety of Call of Duty Modern Warfare (200GB) from the USB drive to the internal SSD drive in 25 minutes.
Yeah the 7 minutes for AC at 40GB is roughly 100MB/s. I'd love to know what HDD he was using because in theory with something like a 4TB WD Black HDD you could do it another 40% faster.
This is clearly the better way to go for me. On PC I have a 500GB NVme and then a stack of really average sata hard drives (I think 6.4TB totall) i've acquired over the years where I stick my strategy games, movies and pictures, and games I've lost interest in. I'm used to moving things over and I will continue to because flash storage is expensive everywhere.