Toast monetizes payments at a 49 basis point take rate, roughly half of what competitors like Square charge. This significant gap represents a major, underappreciated lever for future gross profit growth as the company scales, without needing to increase prices for its core software subscription.

Stripe's potential acquisition of PayPal is driven by a desire to gain PayPal's strong consumer brand and access to customer bank accounts. This would let Stripe bypass expensive credit card interchange fees, a significant cost advantage that is more valuable than PayPal's technology.

The acquisition's goal is to combine Stripe's merchants, PayPal's consumer accounts, and Block's point-of-sale infrastructure. This creates an end-to-end payment network that can bypass traditional credit card rails, establishing a formidable new competitor to the Visa and Mastercard duopoly.

By encouraging users to save low-cost payment methods (like bank accounts), Stripe's Link product effectively creates a distributed, techno-social renegotiation of interchange fees. It gives millions of small businesses the collective bargaining power that only giants like Walmart traditionally wield against payment networks.

For SaaS businesses that process payments, adding a fee based on Gross Merchant Value (GMV) is a powerful revenue driver. This revenue tends to grow more smoothly and predictably over time compared to spiky usage-based fees (e.g., per SMS), making it more valuable to acquirers.

The payments segment is Kaspi's profit engine, contributing 40% of net income from only 16% of revenue. Its net income margin surpasses 65%—higher than Visa's—because it operates on its own closed-loop rails, eliminating intermediary fees.

Wise is not a bank and cannot lend, but it earns interest on customer deposits held in low-risk assets like short-term bonds. This provides a substantial, diversified revenue stream that grows with its customer base, reducing reliance on transaction fees alone.

When a wallet provider like PayPal offers a co-branded credit card, it's more than a marketing deal. They often sign agreements that make them financially liable for credit losses if the portfolio of users they bring to the partner bank underperforms, a risk detailed in their 10-K filings.

The system of charging retailers an interchange fee (around 1.8%) that is then passed to consumers as rewards (around 1.57%) creates a strong network effect. Consumers are incentivized to use rewards cards, and retailers cannot easily offer discounts for other payment methods, locking both parties into the ecosystem.