Trying to understand rx

Im trying to understand the .rx functionality and understand what it can and can not do.
I may share more things but this is one thing that surprised me. In the upper example I thought I was doing something outrageous, but it turns out it works as expected. But then the simpler case below does not work as expected. I tried multiplying the list by a a dummy rx(1) object but then there are no controls at all.

Oct-30-2023 19-11-55