Is there a rationale, beyond historical accident, why some Mathematica option values are strings, while others are symbols?
It seems natural that some value spaces, e.g. named color schemes, are so numerous and only applicable to
ColorData["HTML"] and so should be strings.
On the other hand wouldn't it make more sense if
PairedHistogram[..., BarOrigin -> "XAxis"] were a built in symbol to be shared as an option value across composite graphics functions?