Clarifications…
We have slightly adjusted the wording of the “Only if Usable” Golden Rule to better clarify the rule’s effect on units not on the battlefield.
The intent of the rule is to prohibit units from having Actions or Situations played on them if they cannot utilize the Action or Situation or, more specifically, any part of the Action or Situation.
As a unit not currently on the battlefield (such as Aerial units, Artillery units, etc.) cannot actually conduct movement on the battlefield, they are not able to utilize the movement portion of any Action or Situation.
Therefore, units not on the battlefield cannot have any Actions or Situations played on them that grants some specific amount of battlefield movement, even if the movement is just one part of the Action or Situation.
It may sound a bit confusing but, as with many of the rules, it will make complete sense when you find yourself in that situation.
The change in wording has been made to both the Combat Cards and Fantasy Cards rules.