WGA+ allows confirmed changes on the day of travel. Change it multiple times if you want. Checking a bag is easy.
WGA allows standby. In practice that means for earlier flights only. Your baggage will probably take the original flight. With high loads you might not get a seat, and if you do it will be one of the least desirable seats.
WGA+ is generally a good deal if you want to fly a different time than you bought.
Or if I downgraded to just WGA I could switch to a different flight but just not the day of travel or a standby basis. Right?
I have a ticket for this Thursday that is WGA+. but I don't think I will need a standby on the day of travel. The phone agent told me that it could not be downgraded to just WGA but I don't think that is right.