Python is compiled to bytecode just like Java and C# - it just also happens to provide an environment out of box that will do it on the fly, and makes it much easier to access the "compiler services" in the standard library (and the built-in `eval`). And it's always been that way. The idea that some languages are "serious" and others are not is already suspect. The idea that being a "serious" language requires being "compiled", or that other languages are just for "scripting", will severely limit you as a developer.