Hookless rims is due to cost though most of those savings really aren’t being passed down to the consumer. It’s either a much simpler mold or you get to skip a few machining steps by going hookless. It most likely also results in higher yields.

They also maybe able to save a low single digit number of grams by either betting better compaction and using less material (if they aren’t machining the hooks) and by not having hooks. But that’s nearly inconsequential