The short answer is "backwards compatibility". The long answer is... well, it's the rest of this video. MORE BASICS: Written with Sean Elliott Graphics by William Marler Audio mix by Graham Haerther 🟥 MORE FROM TOM: (you can find contact details and social links there too) 📰 WEEKLY NEWSLETTER with good stuff from the rest of the internet: ❓ LATERAL, free weekly podcast: ➕ TOM SCOTT PLUS: 👥 THE TECHNICAL DIFFICULTIES: