Ok. So there is a concept in martial arts that a whole bunch of stuff has to have happened before you wind up in that devastating arm bar.
And to be a good martial artist you need to start creating an environment where this arm bar works well before there is an arm bar.
So an arm bar takes two things. For you to isolate their arm and for you to break their posture. (Especially standing because you don't have the advantage of being able to throw your whole body at it.)
Now that is a lot to ask for in a fight. And especially for any period of time it takes to actually arm bar someone. Which is a hell of a lot in four or five punches a second fighting times.
So this is where being incredibly cagey about how people train comes in because this process is almost always short cutted by people who don't have a good understanding of what they are doing. You get these terms like I will use their momentum or take an opportunity or other meaningless phrases.
And what you normally wind up getting is training to reflect when a bad guy does something fundamentally silly for long enough to take advantage of.
Unfortunately even dumb bad guys quite often are not that dumb and will do simple defences that make arm bars basically impossible if you are not that good at them.
(You see this with police a bit where they wind up beating on a guy to get that arm and posture break)
So to get arm bars or arm breaks generally you need to break their posture first. Gain a position and isolate their arm. Unfortunately people spend years on grappling arts to try to get just that bit right. That is an incredibly nuanced process and is the reason good grapplers beat bad grapplers pretty consistently.
So if you are talking about someone throwing some slack punch or making a dead straight arm grab then arm bars, arm breaks and martial arts are simple. Unfortunately they also tend not to work.
So an arm break bar kind of can and kind of can't be substituted as an arm break. Some of them do both. There are some like arm drags where you can pressure the joint but not get it to break. There are some shoulder throws that torque the arm as you fall.
As I said it is complicated.