Maybe I wasn’t clear enough because there are there aspects to this -
1. If F is sold out then there is nothing to buy up to
2. If F is not sold out then the cost to buy up is silly - as others have commented- for what you get
3. If F is wide open, then it becomes a game of chance with regard to using the options that we have to see what pans out. Many, I sense, here are tired of the games of chance where the odds are too much on the favor of the house?

for example - I friend who is financially struggling needed to get to LAX and I purchased her ticket nonstop xxx-LAX. I think the RT flight from the Midwest was about $250. As a potential surprise I also used PP to try and get her an UG. She has zero status and not even a MP member but she is #3 on the list with 6 open in F at t-48. As a 1k who bought the same ticket, using pp or cpu or buy up, what are my F ug chances?

also, maybe #4 is that a lot my OPM work travel is short notice and by the time my travel agents at work actually purchase tickets (which can be 1-2 weeks after a contract is signed for me to commit to travel) not only is F gone, but all the good E+ seats are taken.