I think it’s as much an indictment on falling maths literacy on the population as a whole when converting unit prices to a per-KG price as “complex”.
But that’s really besides the point of the majority of the article, as this is largely about converting customers online orders. If I’m ordering apples online, I’d want to buy on a per-unit basis (eg. 5 apples for the kids lunchbox), I’d be pretty miffed if I ordered 800g online - expecting 5 and only getting 4 bigger ones.
Still, the way this is currently implemented is pretty piss-poor - there generally shouldn’t be a per-unit price; charge per KG based on the final weight of produce selected, even if you give customers an option to buy per unit. But that involves weighing each line individually, slowing down the entire process and staff labour “shopping” for customers is a massive expense.