Yep, traditional thing. Other side of the coin, though... Where was that fella talked about the "good" mistake? If you're carving a portrait of me, then it needs to LOOK like me (good news, you won't need your hair blade). But, you can make that flower look like about anything you want. If you trace a line off just a little, it STILL looks like a flower
Lots of folks seem to think they are not an artist, therefore they shouldn't do this or that. Buddy years ago was a charcoal artist (black and white drawings). Always said, "You can't be scared and be an artist". And somewhere I heard that -- "If you think you can't, you're right".
But by using these "flowers", you're getting comfortable with your use of tools, whether that's bevelers, swivel knives, brushes, the dyes, whatever ... if you make a "mistake", YOU know it and can improve, but meanwhile you have a MARKETABLE PRODUCT (looks like a flower to ME).