Rake .rake subfolder not working

I read that if you create a .rake subfolder, you can run rake from any
subfolder in and it will pickup the rake tasks as long as you put the -g

I have this:


Now when I do:

rake -g -T

I only see the tasks defined in my Rakefile.

Does this work like this or am i confused?

Because I just tested, if I go to a subfolder, rake works fine. Not
what the .rake subfolder is for then?