Async task processing: should you use queue workers or just call the task directly

hey everyone, I'm weighing options for handling background tasks like sending out emails or processing images after a user upload. My usual approach is to spin up dedicated worker services that poll a message queue (like RabbitMQ or SQS). It feels clean and scales well. But for simpler, quick tasks, I've seen some systems just invoke the processing logic directly within the main application thread or a thread pool. What are your thoughts on when direct invocation might be acceptable, or even preferable over a full-blown queue system? Are there specific trade-offs you consider