I think it slightly works different with a dating app. In theory, if the app works you don’t need it anymore. So in their case, it is confident to offer a big discount.
But the overall principle that you should expect the discount to reflect their estimated lifetime value of a customer unless the amount is high enough that the investment return can exceed the regular income. With the exception, as noted by conradfr, that if someone suddenly offers a steep discount it could reflect an attempt to raise expensive capital fast
Assuming you're aware of those factors, it's a useful way of gaining insight into customer retention (assuming they're competent enough to run the numbers...)