Hello! I am still stumbling on the very same issue in february 2026. Here are my 2 cents: when one sorts a column, one expects to sort it by displayed values, and that also holds true for reference columns. That means that available sort options (natural sort or any other that may come to mind) must be those of the displayed value in a reference column. If the displayed column is a TExt column in the original table, then the value displayed is text and must be allowed the options for text.
Best regards,
Xavier Lagraula