Stripe offers simple metering, but in the end, you make the job of calculating metering charges (aggregate all usage and send the value to stripe). It’s becoming harder when you are an API or a cloud company who want to bill a server usage for instance. Calculations are getting heavy, costful and hard to maintain. This is why I do think stripe is not a usage based solution, and also the reason why I decided to create a company trying to solve this pain :)