If a trap is invisible to the AI (as it should be), the move makes perfect sense.

Yep, and the Mechanics also tell the enemy what unit of yours is the most difficult (IE, number of unit*HP and also taking into consideration what damage it can inflict). Repair droids are quite sturdy and numerous for a shooter. And just wait until you meet enemy mages or creatures with magic attacks, they will always go for them with spells...

Dear god, so much gold
 

On my current no loss impossible, with minimal kiting (some maps were left completely open some reason) mage, I had something like 500k after clearing verona and selling every duplicate scroll I could find. To be fair I also bought every item available for neatness lvl 3. The point being, I looted every corpse ever, and some verona stacks will net you 5k. Incidentally, I was lugging around 23/400 marauders. Ancient phoenixes ftw. You only need to dig for runes and scrolls.