Personally I think the internationally understood phrase should be used everywhere, but that's just my opinion.
Well here's what you do. Become a U.S. citizen. Ingratiate yourself to the President. Have him appoint you to head the FAA. Issue a decree that "Emergency" will no longer by uttered over U.S. airwaves. Simple really.
"Roll the trucks" however is not standard phraseology in any country as far as I'm aware. IMHO it sounds very unprofessional, whether understood by the controller or not.
Please reference the published ICAO-standard phraseology for a request to have men and equipment standing by. When you can't find it, here's an excerpt from a Eurocontrol publication re ICAO-phraseology that may help you wrap your head around something you seem to not understand...
Phraseology has evolved over time and has been carefully developed to provide maximum clarity and brevity in communications while ensuring that phrases areunambiguous. However, while standard phraseology is available to cover most routine situations, not every conceivable scenario will be catered for and RTF users should be prepared to use plain language when necessary following the principle of keeping phrases clear and concise.
The FAA also recognizes the reality that plain-language plays an essential part of communications between pilot and controller, and their handbook also cites similar awareness. This is especially true during an emergency.
So you may not like the expression "roll the trucks", but every controller in the U.S. knows what a U.S. pilot is talking about when requesting he/she do so. This incident was a U.S. pilot talking to a U.S. controller, and the request made in plain language. That's all that matters. Nobody in the FAA or smoke-filled cockpit cares what your BA cabin crew experience tells you what sounds "professional", it's chirping from the bleachers from someone not even in the game. What's next, his accent didn't sound phony, practiced, or dripping enough to sound "proper"?
This is the 2nd time you've called into question the professionalism of these pilots, who landed an aircraft safely in snowy IMC with a smoke-filled cockpit. Do you think years of reciting scripted PA announcements in the back somehow qualifies you to do so?