2.1.1877 Part 4 Section, RowHidden (Comment's Row is Hidden)

a.   The standard could imply that the RowHidden element may be used to hide a row.

Office uses RowHidden as an indicator of whether the row of the cell to which this comment points is hidden and cannot be used for hiding a row.  The hidden attribute of the row element ("[ISO/IEC-29500-1] §; row") is used for hiding a row.