Why "QSS"?

I'm sure many people have pointed this out before but "quicksilver" is technically one word ( Technically, an archaic one but still) As such, wouldn't it be easier and more intuitive to refer to as just "QS"? Or does "QSS" really stick in the mind that much better?

Note: I understand the deference for a longer acronym in instances where the alternative would be literally one letter. Referring to a one-word item like as "B" instead of "BT" would be really friggin' confusing. X_X