Its just common to say "equivalent of blabla on APS-C". Maybe its just the wrong term used but so what? everybody knows what it supposed to mean.
You'd think so, but >80 posts here and many other threads on the topic suggest otherwise...
What is amazing is that there are so many threads about it. Many people just use crop or ff not both. The reality of it is if you use a crop camera and do not own a FF, the ratios and comparisons are meaningless to you. If you own a FF and do not use a crop it is meaningless to you. Yet it is important to debate what does not matter.
But then again this thread went through 3 pages of perspective talk.