I need to uncheck File > Option Advanced > Use system separators and set the decimal separator to a dot to get Excel to generate English-style CSV files with semicolon-separated values. I can't be bothered to find out where Microsoft moved the CSV export dialog again in the latest version of Office to get it to spit out comma-separated fields.

Point is, CSV is a term for a bunch of loosely-related formats that depends among other things on the locale. In other words, it's a mess. Any sane file format either mandates a canonical textual representation for numbers independent of locale (like JSON) or uses binary (like BSON).

There are office programs that save CSV with the proper comma delimiter regardless of the locale.

There are people who run non-local locales for various good reasons.

There are technically savvy people who have to deal with CSV shenanigans and can and will send it with the proper comma delimiter.