There is no shortage of potential customers, there is a shortage of actual customers. Anything they can do to attract more business helps them. So if they have tons of success stories they'll get far more business.
It would be different in a saturated market, where they might want to try to keep people on the site, but that's not the case here.
It would be different in a saturated market, where they might want to try to keep people on the site, but that's not the case here.