These are good points. I have seen this over and over again - e.g. in a SaaS which is data configured, how do you a) develop and test your work in a sandbox ins

These are good points. I have seen this over and over again - e.g. in a SaaS which is data configured, how do you a) develop and test your work in a sandbox instance, then b) ship those changes across to a prod instance. This is especially complex in highly data driven platforms, e.g. when you can set up custom fields, then base your custom screens on those fields. Then you want to move a screen from one instance to another and it is dependant on several custom fields which may or may not be already present, but may not be at the latest version. Unfortunately virtually no customers nor RFPs ask about these things, so they are a low priority until late in the piece and most platforms do a shit job of it. Your approach is interesting, though most customers in our space at least would blanch if you said words like Python or JS to them, and would not know their git from their got.