True, this will facilitate the step of moving from a WL for confirmation to R class (in PNR) prior to check-in, to the gate control standby list for upgrade.

Remember, there will always be those who will only apply to be placed on the WL at the airport (e.g., those who booked under another marketing carrier's code/codeshare, etc.), and others who may choose to be placed on standby to voluntarily downgrade back to the Y cabin at the gate and give up the R-class confirmation without having to pay any additional fare (e.g., original booking class no longer available; avoids having to pay additional fare collection to return the eUpgrade credits and revert back to Economy).

So the mix can remain volatile right to the end.