* There’s a language which is like Haskell/Elm/PureScript in terms of being purely functional and statically typed. But with syntax that looks more like Excel.
* Purity gets us fearless recalculation.
* Static types let us build UI elements automatically based on the inferred types of code.
* It’s content-addressable like Unison. That means every expression and “cell” has a unique SHA512 hash of it which refers to only that expression.
* Content addressability makes cache invalidation of results trivial.
* It also makes it easy to say “I want exactly this version of that person’s cell and for all time.” Makes it impossible to break someone else’s code once it’s working.
* It also lets you fearlessly federate, if ever needed.
* Content addressed also means you can write tests against code and have them run on every change. Only the tests whose dependencies changed will be rerun. That’s not normal in Python or Haskell, but in a spreadsheet it is.
There are other design choices related to your comment but I don’t want to ramble on.