Don’t measure just for usage metrics. Measure for usage success and satisfaction.
The meal ticket experiment turn out to be an expensive mistake - users never used the feature again after the promo period. From a retention perspective they didn't lose anyone, but the blended CAC for that quarter was horrible.
In hindsight, I think the practice of comparing retention between companies is doing more harm than good.
If your retention rate tells you you are providing a "one-off" service - that's OK. You just have to focus on being a cost-efficient service provider instead of splurging on CAC like everyone else.
I think airline sites are a good example of how to make the most out of one-off payments. Cross sell relevant things (like hotels, car rentals and insurance) so you can get more revenue from that one-off experience.
There’s even companies like Cartrawler that provide this as a service: https://www.cartrawler.com/
No harm, I did like your original comment, sympathize with the misunderstanding, and appreciate your apology.