Its not about size but being able to run a RAID1 setup for speed and redundancy. External USB storage doesn't help here.

"With a USB 3.2 Gen 2 interface, it reaches 1000 MB/s read and 800 MB/s write speeds. It is fast enough to run apps and even boot an operating system from"

That doesn't matter. Fastest PCIe 5.0 NVMe SSD is 14000MB/s. You typically run RAID1 on identical drives. It's also about IOPs, not just speed.