It's a pretty nice play for the company. They have a captive audience and it breaks up the usual "beep... beep... beep..." monotony at the check out stand.
It would be pretty interesting if other brands started to follow suit and vie for your attention at the check-out stand, while providing supermarkets with added revenue. Of course, there's always a possibility that some people might get annoyed rather than entertained, but the same can be said for jingles.
Here's the check out stand in action: