Virtual threads offer the exact same thing as coroutines. It is just in a different format. And Structured concurrency is on the way for them as well. The Virtual Threads solve the color problem, meaning that any function in Java can be either Async or Sync depending on the Thread, and no code needs to be changed. However for a coroutine, you need to have the suspend keyword on the function. This divides the whole Kotlin ecosystem into two colors - suspend and non suspend. No such thing happens with Virtual Threads.

Many people say they did it due to backward compatibility. Actually, they did it as this is the superior approach and due to backward compatibility.