"...go ahead and grab it with flour on your hands". I don't know about you, but I wouldn't grab my smartphone with flour on my hands. Neither would I be trying to take a picture of a barcode with my cellphone in one hand, baby in the other, phone cover flapping down over my hand making it tricky to see what I'm doing while I try to pudge a greasy thumb at the "shoot" button while... blast I dropped it and it's bounced off the granite bench top onto the tiled floor.

"My smartphone has this computational ability" does not equal "my smartphone is in any way designed to be ergonomic or convenient for this task"