Raised caps are easier to find. The space on a flat keyboard barely makes up for the fact that the entire surface feels uniform. Even just Photoshop is easier with the raised caps.
Another thing, Apple's ergonomics are an afterthought. They are going for 90% looks. Jony Ive does not design ergonomic mice and the keyboards keep getting worse. The earlier flat boards were okay, but the new ones almost feel like paper. Awful
I don't know how Ive gets away with the chinese copy-culture style Dieter Ram knockoff designs, but I guess the reality distortion field is still active somehow and selling windshield ice scrapers that also function as Apple wireless mice is a good business decision.