“what is the deal with the round top?”
If you are trying to free climb, those big round tops are showstoppers. The small round top is a significant challenge, especially at thirty feet in the air, where a slip can mean a broken bone, or worse.
Both kinds of round top counter grappling hooks from getting a grip.
I think I read somewhere that most direct falls from 30 ft. or more onto a hard surface are fatal, perhaps not immediately (which might be worse...)