Sometimes, but the situation is in reality worse than that. Excel is also used as the gold standard database/storage/interchange format of record for random shit that clinical researchers have typed in by hand whether directly or transcribed from other notes, often when that data isn't actually fundamentally tabular in nature because people really like working in grids. Even when grids hurt more than help.

A big secret in genetic research is that the MDs, grad students, project managers, and coordinators running the research programs are often not super focused on what well-structured data looks like and don't know what things like "key-value store" or "nested tree-like structure" mean, and even if they did there aren't good GUI tools for entering them anyway, and it leads to countless errors that maybe (here I speculate) they just assume will wash out as noise.

> I think the important question is why is date conversion a default?

Yes, why any kind of conversion is ever the default is a real money question.