I think that keeping your units alive is something that is not mentioned enough. If you can preserve that transport by moving it to the middle east instead of a suicide landing on DEI it can provide value to you throughout the game whether in the med or if you build a factory somewhere it can help move those units around faster.
Then again if japan does not attack J2 you will have more income ( and it actualy payed itself back in 2 turns )
Japan might not be in a position to attack ( or not willing to attack ).
Putting units somewhere where they get killed sounds stupid but if it forces actions by the opponent or if you trade units for time as the allies your doing well.
I think you have to assume that Japan will DOW J2 if they didn’t J1, barring some really non conventional play like Crussia, G1 DOW or whatever. If they don’t J2 DOW, you should rejoice as Allies because that is not normally a very strong move, and positioning for weak axis play is poor play for the allies.