A weird NVMe question.

I was recently Gifted an HP Laptop (HP 15-da0032 wm)
It came to me with 4GB of DDR4 Ram, and a 16 GB Intel Optane NVMe memory.
A sticker on the case says that "Optane Memory Does NOT replace or increase DRAM in your system".
The installed HD is a Toshiba 1TB spinner.

So my question: What good is that 16GB NVMe stick, just sitting in there. I can't see it in Windows 11, so what good is it?

It is a cache drive. It is supposed to speed up the launch of your most used software.
You could use some more actual ram and an actual SSD in the computer.

Thank you, Sir, for your helpful response.

I've lost all respect for HP, putting so little ram and an old style Spinner in such an otherwise Nice little laptop.

How would I ever know, if the motherboard's Memory Manager is using that 16GB NVMe or not?

And, that's a terrible little laptop to get in to, to upgrade the ram or HD. You have to split it, like shucking an oyster. That is, after removing about ten little tiny screws, with six of them being hidden under the rubber feet. I thank a young man on U-Tube, for showing me how to get that case open. He started out with a metal spatula, to crack the case open. And, finished up with a pocket knife.
I did it once, but I don't want to do it again.