Stage variables are typically used to store intermediate results or values that can be reused or referenced within the same stage for calculations, comparisons, and derivations. They are not designed to store values from one row to compare with values in the next row read. Comparisons between rows typically require specialized window functions or retained variables in a sequential processing logic, rather than the use of stage variables. Therefore, storing values from one row to compare with values in the next row read is NOT a valid use of stage variables.