Worker threads provide a mechanism for running code in parallel using a form of threading in Node.js, addressing the problem of CPU-bound operations blocking the main thread and creating delays. However, worker threads have several caveats, including not being true threads with shared state, and having significant overhead and resource consumption when used excessively. They are suitable for CPU-intensive tasks such as job queues or background processing but may not be the best choice for I/O tasks or highly performance-critical code, which can benefit from real threads in other languages like C/C++ or Rust. Libraries such as Piscina, Bree, and Poolifier provide a more convenient interface to worker threads, abstracting away complexity and providing features like thread pooling and concurrency management.