I noted these reports about the upcoming official cargo cover, just after getting my Y and installing a retractable cargo cover from my already-purchased stock of accessories.
I was briefly a little disappointed, but then after studying the photos and discussing with an acquaintance who is familiar with an apparently similar official cover for Model S, I decided that I was glad to have the aftermarket version.
It appears the Tesla cover is a semi-folding hardboard shelf/cover that sits on support "rails" molded into an updated version of the plastic bulkheads on either side of the Y cargo compartment.
MIC Tesla Model Y Now Comes Standard With Cargo Cover: Video
This is OK, and might be an advantage if you plan to put something (lightweight) atop the shelf.
However, my preference is for the retractable style that rolls up into its holder like a heavy window shade, more of a spring-loaded privacy cover than a hard shelf. This is the style I'm familiar with from our other SUVs.
I think the very first examples of these retractable accessory covers for Model Y may have had some issues, with their reliance on adhesive mounting tabs to secure the mounts and hooks. I was concerned about that idea, and I was prepared to drill a few small holes, in order to add push-in automotive panel fasteners for to strengthen the mount.
Happily, I found that the newer versions have very well-designed receiver components that essentially hug the sides and hook over the edges of the factory bulkhead panels, taking all the tension force when the cover is pulled out and hooked in place. There are indeed some small double-sided adhesive tabs provided, but these really don't need to do much; they simply stabilize the receivers so they don't shift or get knocked out of place inadvertently.
(I bought mine from TeslaShields on a pre-order deal, and luckily it arrived just before I needed it so that I could include it in my new‐car "delivery/installation weekend" activities with my son who came down to help me. The timing was getting close, so I contacted Jason at TeslaShields and he arranged for them to express-ship the cover at no extra charge so that I'd have it in time - very much appreciated!)
So the bottom line is that yes, the expected new cover is a welcome upgrade for the Y - but many might actually prefer one of the relatively inexpensive and good-quality aftermarket covers that are now available for the current USA cars.