Is this eSIM better than my resort's Wi-Fi?

Yes, almost certainly. Wi-Fi in many Vanuatu resorts and over-water bungalows is notoriously slow, unreliable (satellite-based), and often very expensive (e.g., sold in 30-minute blocks). A Cellesim eSIM gives you a private, faster 4G connection that works everywhere, in your room, on the beach, and, most importantly, when you leave the resort to explore.