One of the problems I have with Causal is that common/regularly-referred-to constants waste entire rows of my spreadsheet. My spreadsheet canvas mode ends up looking way more complicated, longer, or harder to navigate than it should be with constants scattered throughout my inputs, calculations, and outputs.
The value of cards could be combined with the spreadsheet canvas mode where cards could be created in panes above the column headers, to the left of the variable names, and/or in an upper left quadrant pane for constants that are referred to by specific cells or apply to entire rows as well as columns.
This would allow my inputs, calculations, and outputs to not clutter up my spreadsheet view, and be able to manage my constants & variables in separate areas that could be hidden or shown as needed. If I click in the spreadsheet pane/quadrant, then the spreadsheet view could be maximized and/or shrink the constants panes and vice versa.
Similar to Causal’s roadmap feature of data mapping, it would also be nice to show relationships (lines) between a particular constant and whichever columns and rows refer to it. So if only two columns referred to a property tax constant, then it might show up halfway between those two columns with lines branching out and curving to the center of those two column headers. Whereas another constant might be used in rows and columns, so it might appear in the upper left corner or quadrant and branch out to each column and row that refers to it. Those relationships could be hidden/grayed out or compacted when you’re working on the spreadsheet.
Personally cards aren’t very accessible for me on my 4k screen. I use the upper left portion of Causal way more than the upper right portion let alone click on Workspaces or know that Cards is a Canvas mode. So I think that getting rid of an inaccessible feature like cards doesn’t necessarily mean that it didn’t have any value to users, but that it may have been implemented in an inconvenient way, and users try to work around it without realizing how they could better use that function and solve another problem we face regularly in the app at the same time.