Microsoft has confirmed the Xbox Series X will allow for hot swapping the external SSD. This will allow a console peasant to be able to have more games on hand. While extra SSD units are expensive ($220) they will work directly with the Xbox Series X.
Recall that the Xbox Series X uses PCIe 4.0 so there is a NVMe interface for the SSD unit to afford it very high speed of up to 8GB/s maximum.
Microsoft has worked hard to bring a superior gaming experience to the Xbox. The Xbox Series X represents several breakthroughs in console technology.
Microsoft has not given any projections regarding the number of units they are expected to sell this fall. Sony was forced to reduce inventory as production fell short at TSMC.
Looking forward at the disadvantages of consoles, the idea of removable storage is desirable. The rival PS5 has a M.2 slot on the motherboard which suggests a person could stuff a 2TB M.2 NVMe SSD into the console and have a much better selection of games. Larger M.2 2280 units now span to 8TB but its not known if it can support that much storage.