A single large transport can hold almost as much population as a baseship colonizer, moves faster, and doesn't get used up after the first population drop. In one PBW game, I've got a ringworld barely half a dozen turns after colonization, colonized by a light cruiser, that's already over 10 billion population just from a single large transport repeatedly dropping population on it. Using a baseship colonizer would have required more construction time, more time to fill it up with population, and more time to actually get there and colonize, all just to save a single trip by the large transport. Baseship colonizers are in general counterproductive. Meanwhile, I love being able to emergency build monoliths in 1 turn with that +100% population bonus
. Pretty soon I'll start shipping excess population OFF of that ringworld to the rest of my dozen or so ringworlds, including TWO triple mollies
.