We did a bit of work for laboratories this year and csv is not an uncommon exchange format between labs. In general almost all exchange formats are text based, with labs saying they will upgrade to „modern xml formats“ at some point in the future. So seen in this context a csv or an excel file doesn‘t really surprise me and should probably also be seen in this context.
One lesson I’d draw from that is to favor simple human-readable text formats like CSV, where they’re suitable for the job at hand.