Hey Stefano, OP here. Our goal is to enable any company to bill how they want without hassle or constraints of building out a full subscription stack. Billing models such as tiered/volume pricing and usage billing can get complex but we make them very simple to use. You can often implement these features in places such as Stripe et al but often the minutiae becomes complex. We built the product that can scale from a simple flat price all the way to composite price plans with tiered/volume pricing.