A known sample might draw them in to listen a bit closer to the song. Audiences attention spans are much shorter these days, due to to amount of stimulus surrounding them. The market is flooded, and you've got a very short time to grab someone's attention. This applies to both music and advertising these days.
Using a known sample is more likely to get someone to listen a bit longer, and then you've got a better chance of drawing them in.
This is the reason they use cartoon characters on the side of boring kid's snack foods. You've got to draw them in.
This may not be Be's angle, but it's a common one.