Combat Fabbers?

Apparently they always produce 60M, according to wikis. They use what they are producing when they repair units. So does this mean idle Combat Fabbers boost your econ?

They only produce metal when reclaiming...

Do combat fabbers reclaim buildings faster than other units destroy them? would be a funny way to use them if they do

yes but you would need a metric fuckton of eco for that and godlike micro to get them all reclaming different units with area commands.

They only cost one energy to use though?

One was a temporary hack to fix some math; it was set back to zero a few builds later.