I seem to be confused about what 'hiscore.dat' (and enabling it through MAME's interface 'Plugins' -> 'High Scores' 'ON') actually does, 'under the cover'.
My presumed knowledge so far (and please do correct me if I'm wrong here, I've come here to learn), in random order :
If the original hardware supported 'highscore saving', by writing the information to non-volatile ram (nvram/disk) and therefore surviving power down/up, and if MAME emulates this for the given machine, the contents (highscore and presumably bios settings and such) end up in the 'nvram' folder.
If (automatic) 'save states' are supported by the given machine/game, for which MAME code needs to be added on a per-machine/game basis, and aims to save *all* of the machine's state (like what the memory contents looked like, or what CPU instruction was about to be executed, hardware registers contents, etc.) includes but is not limited to saving the highscore.
Now, assuming the above two are correct (and please, do feel free to correct me if I'm wrong), how does 'highscore.dat' fit in ? How is it different, or similar, or add to, the above two ?
Inquiring minds would like to know.