Another thing I was thinking of:
If you crank up the hitpoints and damage of troops by 10x or 100x, then it would be worthwhile stacking a bunch on your worlds just to be decoy targets for orbital bombardment.
If you've got efficient, low supply cost bombs, you could spend a turn or two to glass it...
but if you've got high-powered infantry it would be simpler to just dump them on the surface so they can rapidly lay waste to the high-hitpoint troop population. If you don't manage to capture, then at least you've cut down on the time it will take to glass the planet as punishment
.