> Do you mean can you add your own nodes? You can but you have to do it in the core code which is C++.

Ouch. I really hope that changes.

> An addon that existed before geo nodes and did similar things, animation nodes, does actually let you write free-form python in the node tree since it was written as an addon. It is very slow compared to geometry nodes though, especially when dealing with lots of objects.

I would like a situation where I can choose to trade speed for easy customization without switching to an entirely different system. I really hope they add scriptable geometry nodes. I just know for a fact that a node system without an escape hatch will be too limiting (and writing C++ is less than ideal and not viable at all if it requires a full recompilation of the app)