Explain
i don't get whats to explain. you were wrong. bricks take up way more data. not even a full loop of slopes is 6 megabytes and is a pain to ghost/save/load, and the slopes map is 500 KB fully packaged and ready to use.
using a brush on the terrain is much faster than building something of the same scale, especially without float cheating. that is why brush tools were designed in the first place, so you didn't have to edit a map vertex by vertex.