The meaning of a value (data type in programming lingo) is not a preference because it is objective, not subjective. It depends on the cell being displayed, not on the viewer in front of the screen.
It's not a setting which determines how a value stored in a sheet is interpreted. It's a setting which determines how inputs are interpreted before being stored.
When you type eg "4/4", "4-Apr", "2025-04-04" or whatever, it is converted to a number based on your local date format. The cell has a date format applied to it so that the number appears as a date. If you send the sheet to someone else, it will display the same numeric value, using their settings to display it as a date.
But GP isn't talking about value, they are talking about process of entering the value, so that _their_ editor (Excel) wouldn't convert it to something weird.
More like I wrote some python code, and want to ensure the IDE doesn't change spaces to tabs. Night theme vs day theme is orthogonal to the code. Date parsing in Excel is not.
Well, no, it isn't because Excel actually changes the underlying data too. It's more like changing the formatting of all the files in the project and deleting all the characters after the 80th column.
I just tested it. The setting applies on data entry but opening a CSV or similar delimited file counts as “data entry”. So if you work strictly with xlsx files you are fine but it will irreversibly convert the values on open for delimited files unless you change the defaults.
Come on, there is no room for anyone to have a preference here when an excel document is meant to be storing the names of genes and would never need to have a date or time in it, and can very easily get corrupted beyond repair if someone turns date conversion on. (For context, genome research is the whole reason this toggle was added in the first place.) Even something like Vim lets you enforce file-specific settings with a header.
At the same time, we're clearly shooting ourselves in the foot by using Excel for this. This feature is just a hodge-podge solution to the problem of Excel not having strict data types. There should be enough cautionary tales (https://eusprig.org/research-info/horror-stories/) for everyone to know to avoid Excel.
Excel is not designed to waste the time of frequent, experienced users while hand-holding casual users. It's designed to make power users very fast and accurate while possibly confusing casual and new users.