The main benefit I get from a class is feedback from the teacher or professor now that I am in uni. So just observing would not work for me.
I do not stress about keeping up, being the leader of the pack etc in the class. I am happy to work at my own pace.
I am someone who will ask a question if I am not sure. I know sometimes people post here how they do not like people asking about something that was already explained, but the way I learn is through question and response. Even if I heard it the first time, I will not have retained the information until I rephrase the information as a question.
Everyone learns differently and if observing the class and doing the work at home works for you, then that is great.
NJ Quilter, I woudl have followed up with the owner of the shop. Often a shop has to order in supplies specific to a class. If a person takes up a seat, but is not purchasing the supplies, the shop could lose out. You could have clarified that with the owner. An employee would be overstepping if they told you it was OK without checking with their boss.