In the B2B world there is a perhaps surprising amount of ad hoc data transfer (transactions, statements) between separate entities using scp/sftp from a cron'ed ksh script written by a junior sysadmin 8 years ago.

Throw a Tectia server in the DMZ, fix the firewall, manage some keys (never change them) and you're good to go! Data at rest security via Zip or PGP for the ambitious.

Occasionally a big enough entity will mandate "everyone will use our data xfer spec" (and it's typically some gnarly XML-infested SOAPy animal). But there's a whole lot of automated business processes doing CSV-over-scp both intra- and inter-company.

Don't even get me started on FTP.