What do you mean? Jupyter notebooks are usually pure Python apart from (sometimes) interactive widgets, which have Javascript behind them since it's in a browser. I don't think this is much use without widgets, so maybe you mean something else?
I mean why can't I write python outside of jupyter and generate these dashboards? Or can I?
You can if you use Panel (panel.pyviz.org); it does not depend on Jupyter in any way (but like Voila, works well in Jupyter).
If you want to avoid Jupyter Notebooks you can look into Dash or Bokeh Server.