A spreadsheet can tell you what's late. It can't show you why — because "why" usually lives in a connection a grid can't draw. Rows and columns are a great representation of independent facts and a poor one of dependent relationships, and most planning problems are mostly the second kind.
Spreadsheets encode position, not relationship
A row in a spreadsheet has a position — row 12, three rows below row 9 — but that position doesn't mean anything about how the tasks relate. Whether task 12 depends on task 9 has to be encoded separately, usually in a text column nobody reliably updates ("blocked by #9"), and read by scanning text rather than seeing a connection. The structure that actually matters — what blocks what — is invisible unless you go looking for it.
Visual layout makes the actual structure of a plan legible at a glance
A board where tasks are nodes and dependencies are drawn lines turns "what blocks the launch" from a research question into something you see immediately: trace the lines back from the launch node and you have your critical path, without computing anything. This isn't a stylistic preference — it's the difference between information that's stored and information that's perceivable.
Where spreadsheets still win
None of this means spreadsheets are bad — they're excellent at exactly what they're built for: tabular, comparable, sortable data with few or no relationships between rows. A list of expenses, a roster, a flat backlog sorted by priority score all belong in a grid. The mistake isn't using spreadsheets — it's reaching for one by default for anything that involves planning a sequence of dependent work, where the relationships are the actual content of the plan.
The tell that you've outgrown the grid
If you find yourself adding a "depends on," "blocked by," or "related to" column and manually keeping it in sync with reality, that's the signal. At that point you're trying to represent a graph inside a table, and the table is fighting you the whole way — the fix isn't a better spreadsheet template, it's a tool that represents relationships as relationships.