> More like trying to explain to people who have only done imperative programming (and that also in JS of all languages) why a render function was necessary.

It doesn't seem all that different from doing your rendering in the WM_PAINT handler, which was already how things were done in the ancient Win32 API (although it's possible [0] to draw outside WM_PAINT).

[0] https://learn.microsoft.com/en-us/windows/win32/gdi/drawing-...