[smokel]

This is an interesting topic. I always loved the idea of extensions, for multiple reasons. But they do have their disadvantages, and I'm eager to find out how extension systems will hold up in the time of LLMs.

A major advantage of (certain) extension mechanisms is that you can update them in real-time. For example, in Emacs you can change functions without losing the current state of the application. In Processing or live coding environments, you can even update functions that affect real-time animation or audio.

Another advantage is that they can pose a very nice API, that allows for other people to learn an abstraction of the core application. If you are the sole developer, and if you can spend the time to keep an active memory of the core application, this does not help much. But it can certainly help others to build upon your foundation. Gimp and Emacs are great examples of this.

A disadvantage is that you have to keep supporting the extension mechanism, or otherwise extensions will break. That makes an ecosystem somewhat more slow to adapt. Emacs is the prime example here. We're still stuck with single-threaded text mode :)