Linus did a review in which they tested PrimoCache. If I recall, it was an application that leveraged RAM for caching that beat both Intel's and AMD's caching solution. Basically, just buy more RAM instead of Optane.
I'm not sure if it builds a pre-fetch file to be used on the next reboot. But if not, you lose all caching performance until you relaunch all your apps again. So if you only reboot your PC once or twice a month like me (for Window Updates), then I think PrimoCache would be the better route to go. If you're having to shutdown and/or reboot often, than Optane would be the best choice I think.
As for Optane being a waste of money. Well, it kinda is. On paper, the specs report Optane having better IOP performance over NAND flash, but by the "how does it feel" metric, I'm not sure you would notice. So instead of Optane, just save the money or put it towards more RAM anyways, a better CPU or GPU. Just my 2 cents.
https://www.romexsoftware.com/en-us/primo-cache/