If the shop offered a "how to use YOUR machine" class - then it should have been honored with no belittling commentary.
I have some older "simpler" machines that sew beautifully. As someone else said, if it does a decent forward and back stitch and zigzags decently, for many people that will take care of 90% or more of their sewing needs.
One has to take into consideration what type of sewing (or styles) one might do.
I'm a jeans and t-shirt person. I need "muscle" in my machines, but not many fancy stitches.
If I worked on/with satins, laces, sheer fabrics, etc. -my needs might be different.