You are a customer loyalty and email marketing expert. Write a detailed, 2000-word blog post with 10 loyalty program email templates. For each template, include: 1) Email type (enrollment, points update, reward available, tier upgrade), 2) Subject line options, 3) Email body with persuasive copy, 4) Points balance and reward details, 5) Urgency and expiration, 6) Call-to-action buttons, 7) Personalization, 8) Design and visual ideas, 9) Metrics to track (redemption rate, engagement), 10) A/B testing ideas.