Even if you are not going to develop any major apps in Smalltalk, its a language worth learning. Teaches you a lot about OO programming

I agree that it is a language worth understanding. However the OO model of Ruby is identical. Without the drawbacks of being an image based language. So I'd suggest learning that instead.

For those who don't know what I am talking about, there are several families of languages where the state of your program is kept within an image. The upside of this is that you can integrate everything together in a really neat way and build neat tooling with introspection. The downside is that you have just made what's going on not visible from the filesystem, and have to replace all of the tooling that you're used to. You know, things like your favorite editor, command line programs, source control...

If you switch languages regularly (which most developers do in my experience), being able to use your favorite toolset everywhere turns out to be more important than being able to build an ideal toolset for only one language.

> The downside is that you have just made what's going on not visible from the filesystem, and have to replace all of the tooling that you're used to. You know, things like your favorite editor, command line programs, source control...

While Pharo (and Squeak, etc.) have baked in editors and source control, Pharo has integrating with general tools as a design goal. It includes an integrated Git client and can load packages from or move them into a Git repository.

Integrating with general tools may be a design goal. Yet it clearly isn't fully there. A filesystem based language does better without even trying.