At first blush, Berkshire Hathaway's recent early-stage fintech investments may seem out of place. But they do fit with Warren Buffett's longtime strategy of making multiple bets across an entire industry. Berkshire's newest industry bet appears to be on payments. In addition to the start-ups revealed this week, Berkshire Hathaway has a significant stake in the three largest U.S. incumbents - Visa, Mastercard and American Express