Much lower latency. Optane doesn't have any of the "page" / "cell" bullshit that flash imposes, so there's really no need for buffers at all. Writes just go straight to disk basically, at almost zero latency, NVMe itself imposes much more latency than the actual reads/writes.

I think of optane not so much as a mass storage device, and more as a fast scratch space. The perfect place to put your swap partition, to use as cache in front of slower storage, the scratch space of an algorithm that starts using disk space to save memory, or the intermediate output of your compiler.

Optane has insane write endurance. Speed is good as well. It is expensive for sure but I guess it can be justified for some database use.

Orders of magnitude better wear capabilities and much faster at low queue depth operations

If you're doing lots of writes it will not wear out the same way an SSD would. Also it's very fast, but these days not as fast as the best NVMe SSDs you can buy now.