It has been clear for several years now that upgrades are no longer the primary benefit of medallion status at any level.

Delta is selling F tickets for decent prices, and this is a win for most customers because we are given the option of sitting in F. When domestic F used to be $2K+ for an advanced purchase mid-con flight, it was not really an option for most people (because it was such a waste of money), and some people got lucky with upgrades sometimes.

WFBF used to be an annoying and unhelpful comment, IMO. Now it's actually true.