No way, don't ever do your Ld missions on Elo mode, unless it's the start of the week where you can afford to lose. If not, go to the Lost Warehouse or Survivor, even Fights for the free 50 clintz (and 1 credit?)
@Elim Garak: If you want to get all the cards or complete all the missions then Lds are important to do (ive currently done all Ld missions that have been releast appart from the last 2 Ulu ld ones but thats because im doing them inbetween revison and other things).
I have done all the ld missions (appart from room specific ones in fight club).
I have no plan to get all the cards, actually i sell any cards which is not kept for selling later or not elo capable ( by elo capable i mean pretty good card often played in elo ). I find it easier to make decks this way most clans have about 4-10 cards i use. Apart from bonnie ld i wouldn't bother with any of them and bonnie is banned.
I only play elo so any t2 who has the deeper pocket cards are worthless to me