Because honestly; I feel this secondary meaning is a buzzword transferred from the first meaning which actually has meaning, but in the secondary case it's simply used to use an expensive word without understanding it.
Edit: Another example is significant digits. Significant digits is a much older concept than significance in statistics, and maps much better to the original meaning of significance. Basically significant things are things you can't ignore when you do your analysis.
That doesn't answer what I asked: what exactly is the meaning here because I remain unconvinced that it's not simply an empty buzzword inserted that transferred from it's usage of statistics, especially when used in conjunction with percentages.
> Edit: Another example is significant digits. Significant digits is a much older concept than significance in statistics, and maps much better to the original meaning of significance. Basically significant things are things you can't ignore when you do your analysis.
Indeed, and that has a meaning that I understand which is also morphologically transparent, but in this supposed meaning of the word which you've to elaborate upon it is neither morphologically transparent, nor do I actually see any meaning in it and I still feel it's used as a buzzword to simply make use of a fancy word for it's own sake.
As for what it means: "important and deserving of attention; of consequence" (https://www.dictionary.com/browse/significant)