Even though I am an Optane fan I do concede that for the most part Optane is somewhere between an inefficient use of $ and a tech demo really only suitable for enthusiasts.
That said, there does actually seem to be a specific use case where Optane is the right choice in terms of both price and performance.
If you are about to build a new system and the SSD that best suites your needs is a 2TB 970 EVO/Pro then you can save some $ (more than 100$) and get much better 4KQ1T1 performance by combining a 2TB 860 EVO and a 58GB 800P. Optane cache also seems to be doing something similar to Samsung Rapid Mode and AMD StoreMI driving sequential read speed way up. My travel laptop has a very similar configuration and this is how it performs:
Keep in mind that you will need to very carefully research laptops if you want to replicate this as very few gen 8 laptops support both SATA and NVMe at the same time. 8th gen Desktops on the other hand should all support this configuration.
That said, there does actually seem to be a specific use case where Optane is the right choice in terms of both price and performance.
If you are about to build a new system and the SSD that best suites your needs is a 2TB 970 EVO/Pro then you can save some $ (more than 100$) and get much better 4KQ1T1 performance by combining a 2TB 860 EVO and a 58GB 800P. Optane cache also seems to be doing something similar to Samsung Rapid Mode and AMD StoreMI driving sequential read speed way up. My travel laptop has a very similar configuration and this is how it performs:

Keep in mind that you will need to very carefully research laptops if you want to replicate this as very few gen 8 laptops support both SATA and NVMe at the same time. 8th gen Desktops on the other hand should all support this configuration.