For consumers notebook, Optane could be fast swap drive. It's pity manufacturers didn't get this done. Swap should be just fast to make application switch fast enough. Optane could do it.
Where I'd expect the technology to really shine is in flash controllers: give that thing a generous serving of optane cache to play with in its fancy wear leveling rites, power-loss-persistent and sufficiently closely integrated (same board) to allow software to confidently assume "committed" without the flash even touched if the write happens within a tight working set (you might want to set certain file system parameters up for "it's ok to write the same address many times"). You could even include the optane in the advertised capacity! And the swap space use case would be included without even trying.
It achieved 14us latency (by acking writes before they hit flash) which is extremely good (better than today's fastest SSDs) but the 32G Optane cache doesn't go very far when most enthusiast consumers are gamers that blow the cache every time they download an update. A lotta games are also larger than 32G so if you use more a few large programs, the cache just isn't large enough. So you end up with a product that's kinda expensive, but still not quite good enough to take the performance crown.
The real issue was size. I've got 100M CPU cache (5800x3d), 24G VRAM (3090), 64G DRAM, and 2TB flash. I'd need at least 128G of Optane for it to make sense in my cache hierarchy and improve game load times. I could get the $3000 data center Optane SSDs, but that's kinda hard to justify when it's as expensive as my entire PC.