There’s a minor typo in Romaing … and it seems to be missing the username at the beginning of the path.
Since things such as that are SO easy to overlook, I generally suggest leaving the databasepath at its default.
But, if you DO change the path, upgrading Gramps should read the old path from the gramps.ini and transcribe it to the new one.
The general rationale for a Preferences item is for people using Gramps on multiple terminals in a home network. So the path can be easily changed from a local drive to a network storage location.