Let's say you have 100,000 rows of data, and in a column all but 3 of those values look like dates. In a real office, which is more likely: that you are working on some set of data that just happens to look like a date 99.997% of the time but isn't a date, or some guy mis-entered or modified 0.003% of the data?

The I-want-to-put-data-in-my-table-which-closely-resembles-an-incredibly-common-format-but-is-problematic-if-mistaken-for-that-format-oh-and-I-can-not-be-bothered-to-google-how-to-turn-off-autoformat niche is not very large. I don't work for microsoft and I don't have copies of user data, but I would be willing to bet my entire life savings that over 95% of the time someone pastes a series which appears to have mismatched data types in the columns, the series actually does have mismatched data types in the columns.

Sounds a bit contrived in this context.

I'd rather think of 100 000 rows where some of them looks like like a date.