Why? It's easy to remove and you don't have a card protruding out of the system.
1. Detach the stand via the screw.
2. Remove the side plate.
3. Unscrew the NVMe cover.
4. Insert the NVMe.
5. Screw the cover back on.
6. Put the plate back on.
7. Screw your stand back on.
VS
1. Insert the Seagate NVMe.
One is more elegant, easier and simpler to do then the other. Note however, I didn't say better then the other. Because while the PS5 method is more complicated to do, it gives you the freedom of choice and likely cheaper SSD prices in the future, assuming the Seagate drive does not drop in price (which is unlikely or might take a while, console accessories always are sold at a premium).
My personal preference is the PS5 way as I can buy a 2TB off the bat (Samsung 980) and reuse it for my PC if I ever need to (such as eventually upgrading to a 4TB SSD). With the Xbox when they release a 2TB card, my 1TB card would only be useful as a backup or to keep some older games on it.