I agree a physical keyboard is better for preventing typos, although one huge advantage of an on-screen keyboard is it can change based on context.

Especially considering the topic of a Python IDE, that seems like an application where predictive text and/or contextual menus could be a huge benefit for many users.

Python is a thoroughly dynamic language, so the scope for "predictive" coding just isn't there. The best language for that is actually something as strict as Agda, where you can build out your code step-by-step by picking your operands from a well-defined list of in-scope bindings, with powerful type constraints guiding your choice at all times. Python is the polar opposite of that, even with the newfangled 'gradual' typing systems that are now being suggested.

I agree even bad keyboards are often better than soft ones, but this calculator isn't qwerty which for my preferences would be too large a disadvantage even over a phone's soft keyboard.

Now, if you could attach a USB keyboard to the calculator, that would be perfect.

It is possible to attach a USB keyboard using a USB-A to USB mini-A adapter. This feature was added to OS 5.1.5.