Because it doesn't clarify nor is it more concise than the alternatives.
A good example of this is "learnings". I have seen multiple managers use the word "learnings", usually in in phrases like, "What were our learnings from this?" Or, "What learnings can we take away?" But there's already a perfectly fine word to use: lessons! The only reason to use "learnings" instead of "lessons" is to show that you're a serious manager. It's just empty signalling.
Similarly, "ring fence". Is it really that much better than, "set aside"? Does it add any nuance, or is it just meaningless change for change's sake?
I am far more tolerant of jargon in law and technology than I am of it in business, because, in my experience, legal and technology jargon does function as shorthand, putting complex topics into a labeled box that allows the speaker to quickly make their point without having to repeat a bunch of knowledge that the audience can be assumed to be familiar with. Business jargon, on the other hand, is far more often merely different for the sake of being different.