[coldtea]

>1. there's nothing useless about it

Opportunity cost. It slows down the parsing for support of something that nobody has ever seen in the wild (not to mention it doesn't even match the name of the format, but let's get past that since we already use ; | and others).

Plus I can't even imagine a use case that would make it a good idea to use that over a simpler delimiter, or even the special purpose ASCII delimiter character. Can you?