They need to make a new money.

3/20/20s were mostly duped, same for the High Runes in the past, 40/15ias, 40/15max, 40/10min jewels etc.

On Ladder, you can upgrade the runes, even though it may not be a common practice for people to take, say, 4 Um + 2 topaz to make 2 Mals, and using that + an amethyst to yield an Ist.

But Runes really can be a curreny, as least on Ladder. By the way, Pul and Lum are not hard to find at all comparing to other high runes. Hephasto quest can drop up to Um rune in Hell, and I think Countess still have a higher chance to drop runes (if...they didn't change that).