Emptying the basket is a waste of time!? Opinions needed

This has happened before. I am not normally an angry person and have, over many illustrious years, become very relaxed about things out of my control..... But super market checkouts still irritate me. I place my hand basket on the conveyer belt. Still full. Normally I would place all items onto the belt, but was laden with othe bags. The subsequent exchange went something like this (with a touch of poetic license, COT is checkout teenager)
COT "please empty the basket"

Me "why?"

COT "please empty the basket"

Me "look. What is the difference between taking items out of the basket compared to off the belt. It all ends up in a pile over there anyhow. Surely its more efficient to save the extra step and just scan items direct from the basket?"

COT "please empty the basket"

Me "why?"

COT glares at me

Me ..... Reluctantly empties basket

..... Am I wrong? If it had been harrods of London where 2 additional staff co-ordinate packing of your fur lined shopping bags for optimal weight and balance I would kind of understand. In that case the degree educated check out professional would scan items. Based on the same weight balance metics.

But this wasn't harrods. This was manly aldi. They don't even put items into bags for you. Whigh I don't mind. The prices are great and I like that. But surely this backs up my pov that emptying the basket onto the belt is a complete waste of time and I can spend it more fruitfully reading the strategically placed copy of "hello" or similar which I would never buy but when you have time to kill as your basket passing along the belt its a good time to find out if Britney spears has finally split up with Kevin......