I think it really depends on the CNA you are working with. When I worked in ICU I wanted to learn everything so I was always asking the nurses questions. After awhile they started allowing me to help them do more and more nursing tasks and soon they allowed me to do some things that they normally did (that was allowed to legally be done by an aide). I learned a great deal and they had less to worry about.
In some facilities they no longer allow aides to take vitals and I have been an aide for over 30 years we used to do this all the time so I feel a little “put out” that we can no longer do something we have always done. Here in WI they aren’t even teaching it in CNA classes anymore which I think is ridiculous.
If you trust your aide let them do things it lightens your load and you may be giving them a learning experience. I am in nursing school and would definitely ask my aide for help.