Notebook Use Case for Mathematicians?

Yes, I did read their README, and I was excited about it. But when I tried it out, I got:

which happens to behave more like a Jupyter notebook, i.e. the existing value of a variable depends on the last executed cell that defined it. Which is not what I’m looking for.

I like Pluto’s, “once you save a cell, it runs it and checks for conflicting definitions, etc.”

From Neptune’s README,

and instead prefer linear , sequential execution.

which I don’t understand if it hasn’t been incorporated yet, or they have an interpretation of “linear” and “sequential” that conflicts with mine.