The VMs are for home "production" use. (The dev VMs live on different storage.)Good is relative - compared to what ? And what are you doing with the vms?
If all you do is run them with no heavy usage then it will not make much of a difference since Optane will cope with sync writes most of the time.
If you do a lot of reads then maybe, if you now have a few spinners or only a few ssds.
If you got 8 800GB SSDs in a mirror pool though (switching 4x2 with 1x2) then probably not
Usage is on the light side for now.
Currently I have a few consumer SSD of various sizes (250/500/960GB) with 1-2 vms on each. The larger vms live on 1TB SSD.
By moving to FreeNas, I can leverage the vmotion option a little faster since the storage would be shared vs local and vmotion wouldnt need to copy data between local storage.
Eventually I like to have more services such as website hosting for self and possibly a few more game client specific deployments accessible from Internet.
I though of the 8x800 vs 2x3.2 drives. But the power increase is double and it fills all my slots (8 empty bays).