alt Hacker NewsAh, yeah I don't have an Aldi near me so I didn't know that. Regardless, the same approach could be applied via emailing coupons with barcodes to scan at the register. It'd just be less convenient for the customer than having it automatically applied via a loyalty card.
The store we usually shop puts out weekly loyalty coupons via email. Sometimes it's a free pint of ice cream. Other times it might be $5 off $20 of spend, etc. To my knowledge they aren't targeting these specials to specific groups because the cashiers always mention them before we even see them appear. It's possible their screen is giving them additional info that isn't mirrored to the screen we see though.