Why does 'tac' mean "reverse abcd to dcba, line-by-line, on the input stream? Human brevity and wit. and then look at the Bloomberg Terminal and ask "Why does 'OTFN'* mean "empty oil tanks departing ports with a cost modifier proportional to the time left in port and risk of loading delays vs. departure cutoffs?", it's for the same human reasons: someone wanted to type as few letters as possible to get something done, and came up with something that seemed good at the time, and it stuck.
Hacking shows always show us people typing three commands and ending up at the [fictional agency of choice] here. Bloomberg can work magic beyond belief with three commands, and even more amazingly dedicated the HELP button on every keyboard to "press it repeatedly and HELP opens the chat to you", which is maybe the best approach I've ever seen.
* OTFN "Oil The Fuck Now" may or may not exist in Bloomberg Terminal, I sadly do not have access :(