Every internal tool has the same origin story. Someone needed to track something -- customers, tickets, inventory, candidates -- and a spreadsheet was the fastest way to start. For a while, it works. Then it doesn't.
Once two people need to update the same spreadsheet at the same time, you're one overwritten cell away from losing real data.
The moment a row needs to move through stages -- new, in progress, done -- a spreadsheet can hold that information but can't enforce it.
Nested IFs, VLOOKUPs chained three deep, a tab nobody's allowed to touch -- these are signs you're already building software, just in the wrong tool.
None of this means the spreadsheet was a mistake. It was the right tool for testing whether the problem was real before spending real effort on it. The mistake is staying there after the answer is clearly yes.