In my opinion, Azure Functions are the better choice when teams are working with event-driven or lightweight workloads that don’t need a constantly running server, such as background processing, scheduled tasks, or simple microservices triggered by HTTP requests, queues, or timers, mainly because they scale automatically and follow a pay-per-use model that reduces operational overhead. On the other hand, Azure App Service is more suitable for full-scale web applications, APIs, or services that need steady performance, longer execution times, and more control over the hosting environment. The key decision factors usually come down to workload type, scaling behavior, cost predictability, execution duration, and how much control the team needs over infrastructure. In short, Functions are ideal for short, reactive, and event-based workloads, while App Service fits better for stable, always-on applications that require consistent performance and richer configuration options.