Spreadsheets force you to pick cells, and the formulas are hidden. They are non-linear, this is linear. They also take a lot of screen space, this is tiny.
Well, since you can literally build game engines in free spreadsheet apps, probably none, but, as you noticed yourself, the selling point is the UX/UI, which seems to be excellent.
If you're only concerned about functionality and not UI, you can always write your calculations in hexadecimal machine code, at least if you don't have the misfortune to be on iOS or some similar game console platform where users aren't allowed to write code. But I think it's more practical to use a better UI.
I haven't used it, but not having to type your data points into separate columns seems to be the benefit here. Instead of forcing rigid entry you can type human-like numeric notes and it will perform the calculations on the fly.