Efficient launch times are crucial for maintaining developer productivity, and using pre-built dev containers can significantly improve development environment efficiency. By leveraging pre-built images, developers can achieve faster launch times and consistent environments across projects, while also streamlining the update process and reducing downtime. The flexibility of dev containers allows developers to customize their environments without starting from scratch each time, but layering features can lead to slower build times if not managed carefully. Pre-building a base image can help find a balance between setup time and launch speed, ultimately enhancing productivity and reducing delays in the development process.