There are so many things I like about this - leaning in to the idea that spreadsheet formulas are a functional programming language, and enhancing that with inferred static types, plain-text persistence, (semi-)structural editing.

And then they go and re-enact Tony Hoare's billion dollar mistake, for no good reason that I can see:

> Some language such as JavaScript uses the concept of an "undefined" value for uninitialized variables or missing property. For simplicity's purpose, we have avoided this concept, treating instances that would be undefined elsewhere as either an error or a blank value. For example, all uninitialized variables start with a blank value. All data types can take on the value of blank.

This is the same spurious "simplicity" seen in Go, and I don't understand the appeal - especially coming from a team that clearly "gets it" when it comes to the importance of expressive types.