That's Excel's type inference causing problems. Not an issue with CSV or any other type of DSV.

It is possible to import a CSV into Excel without type conversion. I just tested it two different ways.

While possible, it's not Excel's default way of doing things. Not always obvious or easy. Not enough people who use Excel really know how to use it.

Regardless, Excel mangling files via type inference is an Excel problem. It's not the fault of the file formats Excel reads in.