Optane/3DXPoint is such a cool tech, it really is depressing it for dead-ended with a company that won't even use it.
Optane cache drives were great - insane endurance, latency and random R/W speeds, exactly what you need in a cache drive. I wish they were still making them, or even that the ones they did make were available anywhere at a remotely reasonable price.
My home server is too antique to use either of the DIMM types available, and only supports up to 512GB of RAM, which it has, so I wouldn't want to replace any in it.
But newer systems can run higher-capacity DIMMs, so I could run the same amount of RAM or more, and still use some high-cap Optane DIMMs in direct mode as a makeshift cache drive.
My current build is still holding up pretty well for my purposes, but it might slowly be getting time to upgrade to something just a wee bit newer (this decade), migrate the newer hardware to that (GPU, NIC, TPUs), and use the old one as a seriously overpowered direct-connected NAS - all 24 drive bays are full already anyway, and at about 40% free space. Then I could give the new box some Optane love...
Really just thinking out loud here though (or, well, out quiet since I'm typing). Started doing that way too often since the Long Covid Brain Fog hit me...