That seems like bizarre behavior for shoppers of a budget price (mostly) grocery who’s rep is, mostly, their low prices.
Any shopper can check the price on every item while keeping their phone in their hand during their entire time in the store but you know how people will start skipping the process as they tire of the tedious chore, especially when comparing the prices on all of the competitive versions and all of the sizes of the product they want to grab.
This and becoming almost entirely self-checkout makes me think the stores have a long-term plan to eventually end the in-store shopping cart process completely.