This isn't just limited to finance. Language creates barriers in all fields, finance and science are the ones most familiar to me.
Programming as well -- someone recently looked alarmed when I told them to "kill" an app on their phone.
Programming as well -- someone recently looked alarmed when I told them to "kill" an app on their phone.
There's also the perennial complaint that sporting analogies and slang make no sense across countries - G. H. Hardy's cricketing analogies and an American professor's baseball or NFL insights are gibberish on the other side of the Atlantic.
If you want to get really nitpicky, halt isn't as absolute and precise as kill. Halt can mean that the app's activity is simply paused, but its resources are still held and it can in the future be resumed from its original position. Kill very much and in no uncertain terms means to immediately terminate the execution of an application without further processing of the current task.
They really aren't interchangeable terms. If you are talking about interchangeability to an end-user who doesn't have such knowledge, I would argue even then some users may understand the different between not using an app and actually terminating it. Such as halting a video vs closing the window. If you are looking for analogies of proof of understanding, people say to "kill the engine" or other mechanical devices. So again, the term "kill" used in reference to terminating things isn't that weird.
The individual who was surprised to hear of killing an app could have been surprised for a variety of reasons, but not in such a way that I think "halt" should be used over kill.
In that respect, "kill" is probably better, since it accurately conveys common ideas like "irreversible" and "messy".
Too often we attempt to explain jargon once, which the audience still doesn't follow, and then we blithely continue using it.
Or worse, acronyms; we think it's sufficient to expand them once and we're done (rather than explain it, and then use something the reader will actually remember in every case).
It's a skill to recognize what level of understanding your audience has, and to be able to explain yourself to their level. We forget either that our audience isn't (whatever), or we forget that the point isn't to turn our audience into (whatever), in fact, that our audience may care nothing about (whatever) -except for the particular bit we're trying to communicate-; we need to use our position as (whatever) to explain a concept in a way that is understandable from the audience's perspective as it is. That's why analogy is often used, for better or ill.