I do like Microsoft's method of expansion better, even if it is quite pricey for the time being. It's pretty cool that you can just pop in a card and have it work, allows easy switching between SSD's if you buy more than 1 expansion card. You should be able to transfer games between 2 different consoles in 2 different rooms quite easily, say if you have a Series X in your living room and a Series S in your bedroom or something.
The only downside is the high price, which competition between Seagate and other SSD manufacturers should solve over time, especially if some of the cheaper SSD manufacturers decide to make them.
The interphase (the connection slot design) and the way the SSD needs to be buildt around it..... makes it unlikely other SSD makers will want to inter the market. Seagate will probably take like large chunk of the pie so, it depends on how well the Xbox series X/S sells. Its probably a expensive gamble for SSD makers to start designing these.
Also the "only" downside? thats a rather huge one. Its gonna be the more expensive way to get a new SSD in.
The plug and play design is neat though, and I like the idea of swapping them in and out, if you happend to buy alot of them. However at 200$+ at peice, thats unlikely to happend imo.
Necro-bump this 2020: http://gamrconnect.vgchartz.com/thread.php?id=229249
Bumb in 2021: http://gamrconnect.vgchartz.com/post.php?id=9047071